chore(workflow): branch-and-PR working method + ADR-number reservation (ADR-0059)

Adopt a trackable working method now the repo is public:
- PRs onto a protected main; --no-ff merge commits; one worktree per branch.
- Reserve-first ADR numbering: scripts/adr-reserve.sh claims the next number
  atomically against main (push = compare-and-swap; ledger
  docs/adr/RESERVATIONS.log), so a number is stable from creation.
- Worktree helpers scripts/wt-new.sh + wt-clean.sh.
- Local-origin test harnesses (reserve 10/10, worktrees 7/7, shellcheck clean).

Record the decision in ADR-0059, supersede ADR-0000's placeholder-until-merge
numbering default, and add the lean CONTRIBUTING.md sections + CLAUDE.md
operational rules.

CLAUDE.md

@@ -272,6 +272,35 @@ Key invariants in the code:
   `git commit` is preceded by an explicit message proposal
   and user approval. No AI attribution in commit messages.
 
+## Branch-and-PR working method (ADR-0059)
+
+The trackable working method for the now-public repo. Full rationale +
+forks in **ADR-0059**; the public-facing subset is `CONTRIBUTING.md`. The
+operational rules an agent must follow:
+
+- **Everything lands via a PR onto a protected `main`.** No direct pushes
+  to `main` (one exception: the ADR-reservation ledger line, D4/D5). One
+  logical change per branch; conventional prefixes (`feat/ fix/ docs/
+  chore/ refactor/ test/ ci/`) matching the commit type.
+- **One worktree per branch — never switch the primary checkout.** Start a
+  branch with `scripts/wt-new.sh <branch>` (creates branch off `origin/main`
+  + a sibling `<repo>-worktree-<segment>` worktree); tidy merged ones with
+  `scripts/wt-clean.sh`. This prevents the same-directory clobber hazard.
+- **Reserve ADR numbers up front** the moment an ADR is known to be needed
+  (branch start *or* mid-branch): `scripts/adr-reserve.sh <slug> "<title>"`
+  atomically claims the next number against `main` (ledger
+  `docs/adr/RESERVATIONS.log`; push = compare-and-swap, retried). The
+  number is stable from creation — cite it freely in commits/cross-refs.
+  **The human runs this script** (its push must originate from them);
+  agents write/test it but don't run its pushing path. Then create
+  `docs/adr/<NNNN>-<slug>.md` + its README index row as normal branch work.
+- **Merge with `--no-ff` merge commits; never rebase or squash** (append-
+  only history). Push and merge are **human steps** — agents prepare
+  branches, edits, PR text, and commit-message proposals, but never push
+  or merge.
+- **Paste the `/runda` / DA review into the PR** so the public repo carries
+  the audit trail.
+
 ## Issue tracking — Gitea via `tea`
 
 Extends (does not replace) the generic Gitea/`tea` safety rules in

CONTRIBUTING.md

@@ -7,6 +7,67 @@ open pull requests there. It's approaching its first public release, so
 the most useful contributions right now are bug reports and rough edges
 you hit while learning.
 
+## Getting set up
+
+The toolchain is pinned with a Nix flake, so dev and CI share one Rust
+version. With [Nix](https://nixos.org/download) (flakes enabled):
+
+```sh
+nix develop          # a shell with the pinned toolchain
+```
+
+Run everything through `nix develop -c …` so you match CI exactly.
+
+## The checks your change must pass
+
+CI runs these on every push and PR; run them locally first, and **check the
+exit code** (a piped `… | tail` can hide a failure):
+
+```sh
+nix develop -c cargo fmt --check
+nix develop -c cargo clippy --all-targets -- -D warnings
+nix develop -c cargo test
+```
+
+All three must be green, with no skipped tests. New behaviour needs tests —
+the suite runs in tiers from unit up to a PTY-driven end-to-end harness.
+
+## Branches and pull requests
+
+- **`main` is protected** and always green; it isn't pushed to directly.
+  Every change lands through a pull request.
+- **Branch off `main`**, one logical change per branch, named with a
+  conventional prefix: `feat/…`, `fix/…`, `docs/…`, `chore/…`,
+  `refactor/…`, `test/…`, `ci/…`.
+- **Commit messages** follow [Conventional Commits](https://www.conventionalcommits.org/)
+  (`feat:`, `fix:`, `docs:` …) and reference the issue (`… (#123)` /
+  `Closes #123`).
+- **Open a PR against `main`.** The CI gate must pass before it can merge;
+  PRs land as merge commits — history is append-only, so please don't
+  force-push or rebase shared branches.
+- Keep one PR to one concern; don't fold unrelated changes together.
+
+## User-facing text
+
+Two rules bind anything a user can see (errors, help, notes):
+
+- **Don't name the database engine** — say "the database" / "the engine".
+- **Don't say "DSL"** — say "simple mode" / "advanced mode".
+
+## Significant changes get a decision record
+
+Architectural or otherwise consequential changes are recorded as ADRs in
+[`docs/adr/`](docs/adr/) — start with [`docs/adr/README.md`](docs/adr/README.md).
+If your change touches a decided area, read the relevant ADR first; if it
+would change a decision, propose a new ADR rather than quietly diverging.
+Opening an issue to discuss a substantial change before building it is
+always welcome.
+
+## Code style
+
+Match the surrounding code — its naming, comment density, and idioms. The
+Clippy nursery lints are enabled and must pass clean.
+
 ## License of contributions
 
 Unless you explicitly state otherwise, any contribution you intentionally

docs/adr/0000-record-architecture-decisions.md

@@ -45,18 +45,23 @@ ADR numbers are a single global sequence, so two branches can each grab
 the `website` branch's ADR-0042 met `main`'s ADR-0042, resolved by
 renumbering the former to ADR-0044.) To prevent it:
 
-**Assign an ADR's number at merge-to-`main`, not at creation.** While the
+**Reserve the number up front, via `scripts/adr-reserve.sh`** (ADR-0059,
-work lives on a non-`main` branch, draft the ADR under a placeholder — an
+which superseded the earlier placeholder-until-merge default). The moment
-`ADR-XXXX` title and a `draft-<slug>.md` filename — and reference it that
+you know an ADR is needed — at branch start or mid-branch — run
-way from any plan or notes. Give it the next free number only when the
+`scripts/adr-reserve.sh <slug> "<title>"`. It atomically claims the next
-branch merges to `main`, renaming the file and updating its references in
+free number against `main` (the remote ref is the registry; a `git push`
-the same step.
+is the compare-and-swap, retried on contention) and records it in the
+append-only ledger `docs/adr/RESERVATIONS.log`. The number is then **stable
+from creation**, so it is safe to cite in commit messages (immutable under
+the no-rewrite rule), in other ADRs, and in the PR from the first commit.
+Create the ADR as `docs/adr/<NNNN>-<slug>.md` and add its README index row
+as part of the branch's normal work.
 
-A number is "taken" only once it appears in `main`'s `docs/adr/README.md`,
+A number is "taken" once its ledger line (or `NNNN-*.md` file) is on
-which is the single source of truth for the next free number — never
+`main`; the script reads both to compute the next free number — never
-compute "next" from a feature branch. A branch that genuinely needs a real
+compute "next" by hand from a feature branch. The full rationale (why
-number up front may instead reserve one by landing a stub index entry on
+reserve-first beats number-on-merge, issue-number ids, or an allocator bot)
-`main` first, but placeholder-until-merge is the default.
+is in **ADR-0059**.
 
 ### Subproject ADR namespaces
 

docs/adr/0059-dev-workflow.md

@@ -0,0 +1,181 @@
+# ADR-0059: Branch-and-PR working method — worktrees, merge commits, and reserve-first ADR numbering
+
+## Status
+
+Accepted — **2026-06-23**, on branch `chore/dev-workflow` (pending merge).
+Number **0059**, the second ADR reserved via the reserve-first flow this
+ADR itself defines (the first was ADR-0058). Updates the **Numbering
+discipline** section of **ADR-0000** (supersedes its placeholder-until-merge
+default with reserve-first). Does not affect the subproject ADR namespaces
+(`docs/website/adr/`, `docs/ci/adr/`).
+
+## Context
+
+The repository is now public, and feature work is moving from
+commit-straight-to-`main` toward branches. A public, multi-branch project
+needs a written, trackable working method instead of ad-hoc habits.
+
+The sharp edge that forced the issue is **ADR numbering**. ADR numbers are
+a single global integer sequence; two branches that each grab "the next
+number" collide on merge (this happened, and was the original motivation
+for ADR-0000's numbering rules). The deeper problem is fundamental:
+
+> A contiguous integer requires a single allocator. Plain git branches have
+> **no shared allocator** until they reconverge at merge — so any number
+> claimed independently on a branch is speculative and can collide.
+
+Earlier work papered over this for two long-lived subprojects by giving
+them their **own namespaces** (`ADR-website-NNN`, `ADR-ci-NNN`), which is
+right for a nameable body of decisions but doesn't generalise to every
+feature branch. ADR-0000 also wrote a **placeholder-until-merge** default
+("assign the number at merge"), but it had never actually been exercised,
+and exercising it revealed two fatal frictions:
+
+1. **ADR numbers are referenced from the first commit onward** — in commit
+   messages (which are immutable under our no-rewrite rule, so a wrong
+   number there is wrong *forever*), in other ADRs, in the PR. A number
+   that only crystallises at merge leaves every earlier reference dangling.
+2. ADRs are *not* low-collision in practice: they're born precisely on the
+   **long-lived feature branches most likely to run in parallel**, so
+   "rare collision" is not a safe assumption.
+
+So the requirement is a number that is **stable from creation, contiguous,
+and collision-free** — which is only possible by acquiring a lock *up
+front*. The insight that unlocks it: **`main` is the registry and an atomic
+`git push` is the lock** — git serialises ref updates, so a push is a
+compare-and-swap. We just have to acquire it *before* referencing the
+number, not at merge.
+
+This is a **genuine-choice** area (reasonable practitioners run GitHub
+Flow, Git Flow, trunk-based, etc.); the decisions below adapt mainstream
+practice to this repo's constraints (append-only history, self-hosted
+Gitea, solo-with-subagents development) rather than claiming a canonical
+default.
+
+## Decision
+
+### D1 — Everything lands via a PR onto a protected `main`
+
+`main` is always-green and protected; no direct pushes (one narrow
+exception — D4). Every change is a branch + pull request onto `main`. One
+logical change per branch/PR. Branch names carry a conventional prefix
+(`feat/ fix/ docs/ chore/ refactor/ test/ ci/`) aligned with the commit
+type. PRs reference their issue (`Closes #N`); the review we already
+perform (the Devil's-Advocate / `/runda` pass) is pasted into the PR so the
+public repo carries the audit trail.
+
+### D2 — One worktree per branch (never switch the primary checkout)
+
+Each branch is developed in its **own git worktree**, a sibling of the
+primary checkout named `<repo>-worktree-<last-segment-of-branch>` (the
+convention already in use for the `website` and `ci` worktrees). Switching
+the primary checkout's branch while another shell sits in the same
+directory is how work gets clobbered — worktrees make that impossible.
+Helpers:
+
+- **`scripts/wt-new.sh <branch>`** — fetch `main`, create the branch off
+  `origin/main`, and add the sibling worktree; prints its path.
+- **`scripts/wt-clean.sh [--dry-run]`** — prune stale entries and remove
+  worktrees whose branch is merged into `origin/main` (refuses dirty ones;
+  never touches the primary or current worktree). Run it whenever.
+
+### D3 — Merge commits (`--no-ff`); never rebase or squash
+
+Branches land with a **merge commit** (`--no-ff`). This is the only
+strategy consistent with the project's append-only / no-history-rewrite
+rule: squash and rebase-merge both rewrite history. Fast-forward-only is
+out because it would require rebasing branches onto `main`. History gains
+merge bubbles; that is the accepted cost of never rewriting.
+
+### D4 — Reserve-first ADR numbering via `adr-reserve.sh`
+
+ADR numbers are **reserved up front, the moment you know an ADR is
+needed** — which may be mid-branch or late, so reservation is decoupled
+from branch creation. `scripts/adr-reserve.sh <slug> [title]`:
+
+1. reads an append-only ledger (`docs/adr/RESERVATIONS.log`) plus the
+   existing `NNNN-*.md` ADRs on `main`; next = highest + 1;
+2. appends `<NNNN> <slug> <date> <title>`, commits, and **pushes to
+   `main`**;
+3. if the push is rejected because `main` moved (someone reserved first),
+   it re-fetches, recomputes, and retries — the push is the compare-and-swap,
+   so allocations are unique by construction, not by luck.
+
+It runs from any branch/worktree without touching the working tree (it does
+the allocation in a throwaway worktree on a detached `origin/main`), and on
+a *non-race* rejection (e.g. protection misconfigured) it **aborts loudly**
+rather than spinning. The number is therefore **stable from the moment it
+returns** — safe to cite in immutable commit messages and other ADRs from
+the first commit, which is what the references-problem (Context) demands.
+
+The ADR file is created as `docs/adr/NNNN-<slug>.md` in the working branch
+and its README index row is added there as normal work; the ledger line on
+`main` is the allocation record and never conflicts with feature work
+(feature branches don't touch it). The ledger may be pruned later; it's a
+lock record, not state. **Collisions** (two reservations in the same
+instant) are resolved automatically by the retry; the README index edit is
+a secondary tripwire if one ever slips through.
+
+This **supersedes ADR-0000's placeholder-until-merge default.** Subproject
+namespaces (`ADR-website-NNN`, `ADR-ci-NNN`) are unchanged — they solve a
+different problem (a nameable long-lived body of decisions) and stay.
+
+### D5 — Branch protection configuration
+
+On `main` (Gitea → Settings → Branches):
+
+- **Require pull requests** + **require the CI status check** (`ci / gate*`)
+  to pass before merge, and **block merge of out-of-date branches** (this
+  is what makes "`main` is the lock" airtight for the substantive merges).
+- **Whitelist the repo owner for direct push.** This is the one narrow
+  carve-out that lets `adr-reserve.sh` push the append-only ledger line
+  directly; everything substantive still goes through a PR. Without it the
+  reserve script aborts with a clear "is the owner whitelisted?" message.
+
+### D6 — Who does what
+
+**Pushing and merging are human steps**; automated agents prepare branches,
+edits, PR text, and commit-message proposals but never push or merge. The
+reserve script is **run by the human** (so the ledger push originates from
+the human's invocation, consistent with that rule) — agents may write and
+test the script but not run its pushing path.
+
+## Forks (all user-chosen, 2026-06-22/23)
+
+- **Merge commits (`--no-ff`)** over squash or fast-forward-only — the only
+  option consistent with append-only history (D3).
+- **Strict everything-via-PR** over allowing trivial direct commits — one
+  carve-out only, the reservation line (D1/D4/D5).
+- **Branch protection enforced in Gitea** over convention-only — mechanical
+  guarantee for a public repo (D5).
+- **Reserve-first contiguous integers** over: number-on-merge (rejected —
+  breaks immutable references), Gitea-issue-number ids (rejected — non-
+  contiguous, overlaps the legacy 0001–0057 range), or an allocator bot
+  (rejected — machinery + a PR-rule exemption). Reserve-first keeps the
+  short stable "ADR 0059" reference and needs no new infrastructure beyond
+  one script (D4).
+- **Worktrees prescribed** over single-checkout branch switching — prevents
+  the same-directory clobber hazard (D2).
+
+## Consequences
+
+- A written, public-facing **`CONTRIBUTING.md`** (lean: setup, the CI gate,
+  branch/PR conventions, the user-facing copy rules, "significant changes
+  get an ADR"). The maintainer-facing mechanics (worktrees, the reserve
+  lock, the whitelist) live here and in `CLAUDE.md`, not in CONTRIBUTING.
+- Three scripts enter `scripts/`: `adr-reserve.sh`, `wt-new.sh`,
+  `wt-clean.sh`, each with a local-`origin` test harness
+  (`test-adr-reserve.sh`, `test-wt.sh`) — the reserve script's allocation,
+  idempotence, race-retry discriminator, and hard-abort paths are all
+  covered (the real-remote push is exercised by the human running it).
+- `docs/adr/RESERVATIONS.log` appears on `main` as the allocation ledger.
+- ADR-0000's Numbering-discipline section is updated to point here.
+- `CLAUDE.md` gains the operational rules an agent must follow.
+
+## Out of scope
+
+- **Migrating the legacy `0001–0057` ADRs** to any new scheme — they keep
+  their numbers; reserve-first applies going forward (next is `0060`).
+- **Automating PR creation/merge** — humans push and merge (D6).
+- **A CONTRIBUTING-side description of the reserve lock** — it's maintainer
+  infrastructure, not contributor guidance (kept here instead).

scripts/adr-reserve.sh

@@ -0,0 +1,141 @@
+#!/usr/bin/env bash
+#
+# adr-reserve.sh — atomically reserve the next main-sequence ADR number.
+#
+# WHY THIS EXISTS
+#   A contiguous ADR integer needs a single allocator, but git branches have
+#   no shared allocator until they merge — which is why two parallel branches
+#   that each invent "the next number" collide. This script makes `main` the
+#   allocator and an atomic `git push` the lock:
+#
+#     1. read an append-only ledger (docs/adr/RESERVATIONS.log) + the existing
+#        NNNN-*.md ADRs on main; next = highest + 1;
+#     2. append "<NNNN> <slug> <date> <title>" to the ledger, commit, PUSH;
+#     3. if the push is rejected because main moved (someone reserved first),
+#        re-fetch, recompute, and retry.
+#
+#   A push to a ref is a compare-and-swap, so the remote `main` ref is the
+#   mutex and step 3 is the retry-on-contention. The number is therefore
+#   stable from the moment this returns — safe to cite in commit messages
+#   (which are immutable) and in other ADRs from the very first commit.
+#   (Decision recorded in the dev-workflow ADR.)
+#
+#   It runs from ANY branch / worktree / directory inside the repo and never
+#   touches your working tree: the allocation happens in a throwaway worktree
+#   on a detached origin/main.
+#
+# PREREQUISITE
+#   You must be allowed to push directly to `main` (the repo owner is
+#   whitelisted in the branch-protection rule for exactly this). Everything
+#   substantive still goes through a PR; this one append-only ledger line is
+#   the sole sanctioned direct push. If protection rejects the push, the
+#   script aborts with a clear message rather than spinning.
+#
+# USAGE
+#   scripts/adr-reserve.sh <slug> [title...]
+#   scripts/adr-reserve.sh clause-concept-hints "Clause-concept hints"
+#
+# OUTPUT
+#   The reserved zero-padded number on stdout (e.g. 0058); progress on stderr.
+
+set -euo pipefail
+
+log()  { printf '  reserve-adr: %s\n' "$*" >&2; }
+die()  { printf 'reserve-adr: ERROR: %s\n' "$*" >&2; exit 1; }
+
+REMOTE="origin"
+BRANCH="main"
+LEDGER="docs/adr/RESERVATIONS.log"
+MAX_ATTEMPTS=20
+
+[ $# -ge 1 ] || die "usage: adr-reserve.sh <slug> [title...]"
+slug="$1"; shift
+title="${*:-}"
+
+# Slug must match the NNNN-<slug>.md filename convention.
+[[ "$slug" =~ ^[a-z0-9]+(-[a-z0-9]+)*$ ]] \
+  || die "slug must be lowercase-kebab-case (got: '$slug')"
+
+root="$(git rev-parse --show-toplevel 2>/dev/null)" || die "not inside a git repo"
+
+log "allocating next ADR number for '$slug' against $REMOTE/$BRANCH"
+git -C "$root" fetch --quiet "$REMOTE" "$BRANCH" || die "git fetch $REMOTE $BRANCH failed"
+
+# Throwaway detached worktree on origin/main — isolated from your working tree.
+tmp_base="$(mktemp -d)"
+wt="$tmp_base/wt"
+# shellcheck disable=SC2329  # invoked indirectly via `trap cleanup EXIT`
+cleanup() {
+  git -C "$root" worktree remove --force "$wt" >/dev/null 2>&1 || true
+  rm -rf "$tmp_base"
+}
+trap cleanup EXIT
+git -C "$root" worktree add --quiet --detach "$wt" "$REMOTE/$BRANCH" \
+  || die "could not create temp worktree at $wt"
+
+# Highest number across existing top-level ADR files and the ledger, + 1.
+compute_next() {
+  local max=0 n base
+  shopt -s nullglob
+  for f in "$wt"/docs/adr/[0-9][0-9][0-9][0-9]-*.md; do
+    base="$(basename "$f")"; n=$((10#${base%%-*}))
+    (( n > max )) && max=$n
+  done
+  if [ -f "$wt/$LEDGER" ]; then
+    while read -r num _; do
+      [[ "$num" =~ ^[0-9]{4}$ ]] || continue
+      n=$((10#$num)); (( n > max )) && max=$n
+    done < "$wt/$LEDGER"
+  fi
+  printf '%04d' $(( max + 1 ))
+}
+
+# Idempotence: if this slug is already reserved, report it and stop.
+if [ -f "$wt/$LEDGER" ]; then
+  existing="$(awk -v s="$slug" '$2==s {print $1; exit}' "$wt/$LEDGER" || true)"
+  if [ -n "${existing:-}" ]; then
+    log "'$slug' is already reserved as ADR $existing — nothing to do"
+    echo "$existing"
+    exit 0
+  fi
+fi
+
+attempt=0
+while (( attempt < MAX_ATTEMPTS )); do
+  attempt=$(( attempt + 1 ))
+  git -C "$wt" fetch --quiet "$REMOTE" "$BRANCH"
+  git -C "$wt" reset --hard --quiet "$REMOTE/$BRANCH"
+
+  num="$(compute_next)"
+
+  # Dry run: report the number we WOULD reserve and stop (no commit/push).
+  # Useful for a preview and for testing the read/allocation path.
+  if [ -n "${ADR_RESERVE_DRY_RUN:-}" ]; then
+    log "DRY RUN: would reserve ADR $num for '$slug' (no push)"
+    echo "$num"
+    exit 0
+  fi
+
+  mkdir -p "$wt/docs/adr"
+  printf '%s  %s  %s  %s\n' "$num" "$slug" "$(date +%F)" "$title" >> "$wt/$LEDGER"
+  git -C "$wt" add "$LEDGER"
+  git -C "$wt" commit --quiet -m "docs(adr): reserve $num for $slug"
+
+  log "attempt $attempt: claiming ADR $num …"
+  if push_out="$(git -C "$wt" push "$REMOTE" "HEAD:$BRANCH" 2>&1)"; then
+    log "reserved ADR $num for '$slug' (pushed to $REMOTE/$BRANCH)"
+    echo "$num"
+    exit 0
+  fi
+
+  # Distinguish a lost race (retryable) from a hard rejection (not).
+  if grep -qiE 'non-fast-forward|fetch first|tip of your .* is behind|stale info' <<<"$push_out"; then
+    log "race lost (main moved) — re-fetching and retrying"
+    continue
+  fi
+  printf '%s\n' "$push_out" >&2
+  die "push to $BRANCH was rejected and this is not a race — likely branch \
+protection (is the owner whitelisted for direct pushes to $BRANCH?). Aborting."
+done
+
+die "gave up after $MAX_ATTEMPTS contended attempts — main is changing very fast?"

scripts/test-adr-reserve.sh

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+# Verifies adr-reserve.sh against a local file:// origin (no network/keys).
+# Exercises: number computation, dry-run, real reserve+push, sequential
+# allocation, idempotence, hard-rejection abort (vs infinite loop), and the
+# race-vs-abort discriminator.
+set -euo pipefail
+
+SCRIPT="$(cd "$(dirname "$0")" && pwd)/adr-reserve.sh"
+PASS=0 FAIL=0
+check() { # <desc> <expected> <actual>
+  if [ "$2" = "$3" ]; then echo "PASS: $1 ($3)"; PASS=$((PASS+1));
+  else echo "FAIL: $1 — expected '$2' got '$3'"; FAIL=$((FAIL+1)); fi
+}
+
+T="$(mktemp -d)"
+trap 'rm -rf "$T"' EXIT
+
+# ---- seed a bare origin with ADRs up to 0057 -------------------------------
+git init -q --bare "$T/origin.git"
+git clone -q "$T/origin.git" "$T/seed"
+git -C "$T/seed" config user.email t@t.io
+git -C "$T/seed" config user.name  tester
+mkdir -p "$T/seed/docs/adr"
+echo "# legacy" > "$T/seed/docs/adr/0056-alpha.md"
+echo "# legacy" > "$T/seed/docs/adr/0057-beta.md"
+git -C "$T/seed" add -A
+git -C "$T/seed" commit -qm "seed: ADRs through 0057"
+git -C "$T/seed" branch -M main
+git -C "$T/seed" push -q origin main
+
+# the repo the script runs inside (origin = our bare repo)
+git clone -q "$T/origin.git" "$T/work"
+git -C "$T/work" config user.email t@t.io
+git -C "$T/work" config user.name  tester
+
+run() { ( cd "$T/work" && "$@" ); }
+
+echo "--- Test 1: dry-run computes 0058 (no push) ---"
+out="$(run env ADR_RESERVE_DRY_RUN=1 bash "$SCRIPT" feature-one "Feature One" 2>/dev/null)"
+check "dry-run number" "0058" "$out"
+git -C "$T/seed" pull -q origin main
+check "dry-run pushed nothing" "no" "$( [ -f "$T/seed/docs/adr/RESERVATIONS.log" ] && echo yes || echo no )"
+
+echo "--- Test 2: real reserve → 0058, pushed to origin ---"
+out="$(run bash "$SCRIPT" feature-one "Feature One" 2>/dev/null)"
+check "first reserve number" "0058" "$out"
+git -C "$T/seed" pull -q origin main
+check "ledger landed on origin" "0058  feature-one" "$(awk 'NR==1{print $1"  "$2}' "$T/seed/docs/adr/RESERVATIONS.log")"
+
+echo "--- Test 3: second slug → 0059 (sequential) ---"
+out="$(run bash "$SCRIPT" feature-two 2>/dev/null)"
+check "second reserve number" "0059" "$out"
+
+echo "--- Test 4: idempotence — re-reserving feature-one returns 0058 ---"
+out="$(run bash "$SCRIPT" feature-one 2>/dev/null)"
+check "idempotent re-reserve" "0058" "$out"
+git -C "$T/seed" pull -q origin main
+check "no duplicate ledger line" "1" "$(grep -c ' feature-one ' "$T/seed/docs/adr/RESERVATIONS.log")"
+
+echo "--- Test 5: hard rejection (branch protection) aborts, does NOT loop ---"
+cat > "$T/origin.git/hooks/pre-receive" <<'HOOK'
+#!/bin/sh
+echo "protected branch: push declined" >&2
+exit 1
+HOOK
+chmod +x "$T/origin.git/hooks/pre-receive"
+set +e
+run bash "$SCRIPT" feature-three >/dev/null 2>"$T/err"; rc=$?
+set -e
+check "abort exit code nonzero" "yes" "$( [ "$rc" -ne 0 ] && echo yes || echo no )"
+check "abort cites protection, not a loop" "yes" "$(grep -qi 'not a race\|protection' "$T/err" && echo yes || echo no)"
+rm -f "$T/origin.git/hooks/pre-receive"
+
+echo "--- Test 6: race discriminator matches a real non-ff message ---"
+ff_msg=" ! [rejected]        main -> main (non-fast-forward)
+error: failed to push some refs"
+check "non-ff treated as race" "yes" \
+  "$(grep -qiE 'non-fast-forward|fetch first|tip of your .* is behind|stale info' <<<"$ff_msg" && echo yes || echo no)"
+
+echo
+echo "==== $PASS passed, $FAIL failed ===="
+[ "$FAIL" -eq 0 ]

scripts/test-wt.sh

@@ -0,0 +1,57 @@
+#!/usr/bin/env bash
+# Smoke-tests wt-new.sh / wt-clean.sh against a local file:// origin.
+set -euo pipefail
+
+here="$(cd "$(dirname "$0")" && pwd)"
+WT_NEW="$here/wt-new.sh"
+WT_CLEAN="$here/wt-clean.sh"
+PASS=0 FAIL=0
+check() { if [ "$2" = "$3" ]; then echo "PASS: $1 ($3)"; PASS=$((PASS+1));
+          else echo "FAIL: $1 — expected '$2' got '$3'"; FAIL=$((FAIL+1)); fi; }
+
+T="$(mktemp -d)"
+trap 'rm -rf "$T"' EXIT
+
+git init -q --bare "$T/origin.git"
+git clone -q "$T/origin.git" "$T/primary"
+git -C "$T/primary" config user.email t@t.io
+git -C "$T/primary" config user.name tester
+echo seed > "$T/primary/README.md"
+git -C "$T/primary" add -A
+git -C "$T/primary" commit -qm seed
+git -C "$T/primary" branch -M main
+git -C "$T/primary" push -q origin main
+
+run() { ( cd "$T/primary" && "$@" ); }
+target="$T/primary-worktree-thing-one"
+
+echo "--- wt-new rejects a non-conventional branch name ---"
+set +e; run bash "$WT_NEW" my-thing >/dev/null 2>&1; rc=$?; set -e
+check "bad-prefix rejected" "yes" "$( [ "$rc" -ne 0 ] && echo yes || echo no )"
+
+echo "--- wt-new creates branch + sibling worktree ---"
+out="$(run bash "$WT_NEW" feat/thing-one 2>/dev/null)"
+check "prints target path" "$target" "$out"
+check "worktree dir exists" "yes" "$( [ -d "$target" ] && echo yes || echo no )"
+check "worktree on the new branch" "feat/thing-one" "$(git -C "$target" rev-parse --abbrev-ref HEAD)"
+
+echo "--- wt-new refuses to clobber an existing branch ---"
+set +e; run bash "$WT_NEW" feat/thing-one >/dev/null 2>&1; rc=$?; set -e
+check "duplicate rejected" "yes" "$( [ "$rc" -ne 0 ] && echo yes || echo no )"
+
+echo "--- wt-clean removes a MERGED worktree (and keeps an unmerged one) ---"
+# thing-one: make it merged into origin/main (push its tip to main).
+git -C "$target" commit -q --allow-empty -m "thing-one work"
+git -C "$target" push -q origin HEAD:main
+# thing-two: a second worktree that is NOT merged.
+run bash "$WT_NEW" feat/thing-two >/dev/null 2>&1
+target2="$T/primary-worktree-thing-two"
+git -C "$target2" commit -q --allow-empty -m "thing-two work (unmerged)"
+
+run bash "$WT_CLEAN" >/dev/null 2>&1
+check "merged worktree removed" "no"  "$( [ -d "$target"  ] && echo yes || echo no )"
+check "unmerged worktree kept"  "yes" "$( [ -d "$target2" ] && echo yes || echo no )"
+
+echo
+echo "==== $PASS passed, $FAIL failed ===="
+[ "$FAIL" -eq 0 ]

scripts/wt-clean.sh

@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+#
+# wt-clean.sh — tidy up worktrees whose branch has merged.
+#
+# WHAT it does (safe by default):
+#   1. `git worktree prune` — drop admin entries for worktrees whose
+#      directory is already gone.
+#   2. For every *other* worktree (never the primary checkout, never the one
+#      you're standing in) whose branch is fully merged into origin/main:
+#      remove the worktree and delete the local branch.
+#
+# SAFETY: it refuses to remove a worktree with uncommitted changes (no
+# --force) and only ever touches branches git confirms are merged into
+# origin/main, so unmerged work is never lost. Run it whenever; it's not
+# tied to any moment.
+#
+# USAGE
+#   scripts/wt-clean.sh            # do it
+#   scripts/wt-clean.sh --dry-run  # show what it would remove
+
+set -euo pipefail
+
+log() { printf '  wt-clean: %s\n' "$*" >&2; }
+
+dry=0
+[ "${1:-}" = "--dry-run" ] && dry=1
+
+git rev-parse --git-dir >/dev/null 2>&1 || { echo "wt-clean: not in a git repo" >&2; exit 1; }
+
+log "fetching origin/main"
+git fetch --quiet --prune origin main || true
+
+log "pruning stale worktree entries"
+if (( dry )); then
+  git worktree prune --dry-run -v
+else
+  git worktree prune -v
+fi
+
+# The primary checkout and the current worktree are off-limits.
+main_wt="$(git worktree list --porcelain | awk '/^worktree /{print $2; exit}')"
+here="$(git rev-parse --show-toplevel)"
+
+# Branches fully merged into origin/main (whitespace-trimmed, sans markers).
+merged="$(git branch --format='%(refname:short)' --merged origin/main)"
+is_merged() { grep -qxF "$1" <<<"$merged"; }
+
+removed=0
+# Iterate worktrees: paired "worktree <path>" / "branch refs/heads/<name>".
+path=""; while read -r key val; do
+  case "$key" in
+    worktree) path="$val" ;;
+    branch)
+      br="${val#refs/heads/}"
+      if [ "$path" != "$main_wt" ] && [ "$path" != "$here" ] && is_merged "$br"; then
+        if (( dry )); then
+          log "would remove worktree $path (branch $br, merged)"
+        else
+          if git worktree remove "$path" 2>/dev/null; then
+            git branch -d "$br" >/dev/null 2>&1 || true
+            log "removed worktree $path + branch $br"
+            removed=$((removed+1))
+          else
+            log "skipped $path — has uncommitted changes (remove it by hand)"
+          fi
+        fi
+      fi
+      ;;
+  esac
+done < <(git worktree list --porcelain)
+
+(( dry )) || log "done — removed $removed merged worktree(s)"

scripts/wt-new.sh

@@ -0,0 +1,54 @@
+#!/usr/bin/env bash
+#
+# wt-new.sh — start a branch in its own git worktree.
+#
+# WHY: every branch is developed in an isolated worktree, never by switching
+# the primary checkout (two shells in one checkout is how you clobber work).
+# This creates the branch off an up-to-date `main` and a sibling worktree
+# named to match the repo's existing convention:
+#
+#     <parent>/<repo>-worktree-<last-segment-of-branch>
+#     e.g.  feat/clause-concept-hints  ->  ../rdbms-playground-worktree-clause-concept-hints
+#
+# USAGE
+#   scripts/wt-new.sh <branch>
+#   scripts/wt-new.sh feat/clause-concept-hints
+#
+# Prints the new worktree path; cd there to start working.
+
+set -euo pipefail
+
+log() { printf '  wt-new: %s\n' "$*" >&2; }
+die() { printf 'wt-new: ERROR: %s\n' "$*" >&2; exit 1; }
+
+[ $# -eq 1 ] || die "usage: wt-new.sh <branch>  (e.g. feat/my-thing)"
+branch="$1"
+
+# Conventional prefixes keep branch names aligned with commit types.
+case "$branch" in
+  feat/*|fix/*|docs/*|chore/*|refactor/*|test/*|ci/*) : ;;
+  *) die "branch should start with feat/ fix/ docs/ chore/ refactor/ test/ ci/ (got: $branch)" ;;
+esac
+
+git rev-parse --git-dir >/dev/null 2>&1 || die "not inside a git repo"
+
+# Sibling-of-the-primary-checkout location, matching existing worktrees.
+main_wt="$(git worktree list --porcelain | awk '/^worktree /{print $2; exit}')"
+parent="$(dirname "$main_wt")"
+repo="$(basename "$main_wt")"
+seg="${branch##*/}"
+target="$parent/${repo}-worktree-${seg}"
+
+[ -e "$target" ] && die "worktree path already exists: $target"
+git show-ref --verify --quiet "refs/heads/$branch" \
+  && die "branch already exists: $branch (use 'git worktree add' to attach a worktree to it)"
+
+log "fetching origin/main"
+git fetch --quiet origin main || die "git fetch origin main failed"
+
+log "creating branch '$branch' + worktree at $target"
+git worktree add --quiet -b "$branch" "$target" origin/main \
+  || die "git worktree add failed"
+
+log "ready — cd into it:"
+echo "$target"