docs: move website ADR + plan into a dedicated docs/website/ namespace

The website subproject drew ADR numbers from the same global integer pool
as main, so every merge risked a collision — this already happened twice
(drafted 0042, bumped to 0044, both landing on numbers main had taken; main
has now used 0044 for relationship visualization). Give the website its own
ADR namespace so the two never compete again.

- docs/adr/0044-public-website-...md
    -> docs/website/adr/20260604-adr-website-001.md  (id: ADR-website-001)
- docs/plans/20260604-adr-0044-website.md
    -> docs/website/plans/20260604-website-implementation-plan.md
- new docs/website/adr/README.md index (dated <date>-adr-website-<NNN> seq)
- docs/adr/README.md: drop the 0044 entry, add a namespace pointer in the
  intro (keeps the list tail == merge-base, so main's 0044 merges cleanly)
- ADR-0000: record the subproject-ADR-namespace convention
- update references in STYLE.md, astro.config.mjs, the plan body

Handoff files left untouched as point-in-time history.

docs/website/adr/20260604-adr-website-001.md

@@ -0,0 +1,133 @@
+# ADR-website-001: Public website and documentation site
+
+## Status
+
+Accepted (2026-06-04). Implementation plan:
+[`docs/website/plans/20260604-website-implementation-plan.md`](../plans/20260604-website-implementation-plan.md).
+
+> History: drafted as ADR-0042, renamed to ADR-0044 (each collided with a
+> number `main` had independently assigned — H1a took 0042, compound-PK FK
+> took 0043, then relationship-visualization took 0044). Moved to the
+> website ADR namespace (`docs/website/adr/`, id **ADR-website-001**) on
+> 2026-06-10 to end the recurring cross-branch number collision: website
+> decision records now draw from their own dated sequence and never the
+> main global ADR pool (see ADR-0000 "Numbering discipline"). Content is
+> unchanged from the original draft.
+
+## Context
+
+RDBMS Playground is nearing its first public release and needs a public
+website that does two jobs: **attract** — a landing page that shows the
+playground in action — and **document** — a thorough, canonical reference
+for everything the playground can do.
+
+The documentation-heavy surface is already implemented and verified (full
+simple- and advanced-mode command set, the ten-type vocabulary,
+relationships, constraints, indexes, EXPLAIN, undo/history/replay, projects,
+export/import, the teaching echo, clipboard, friendly errors, tab completion
+and syntax highlighting; 2151 tests passing at the time of writing). The
+site is therefore largely a presentation-and-writing effort, not a
+wait-for-features one. A grounded inventory of what is shippable now lives
+in the implementation plan.
+
+Several choices here had no canonical default; they were settled during a
+planning + `/runda` pass with the user and are recorded below.
+
+## Decision
+
+1. **Stack — Astro 6 + Starlight + Tailwind v4.** Astro's content-first,
+   zero-JS-by-default model with the Starlight docs theme fits a
+   marketing-landing-plus-heavy-docs site better than the alternative
+   considered, SvelteKit + Tailwind (the usual go-to here). Interactive
+   pieces are added as Astro islands (Svelte or vanilla), so Svelte is still
+   available where it earns its place. Tailwind v4 is wired via the official
+   `@tailwindcss/vite` plugin; the `@astrojs/starlight-tailwind` plugin
+   bridges Tailwind with Starlight's theming.
+
+2. **Demo medium — asciinema.** Showcase sequences are recorded as
+   asciinema `.cast` files (text-based, small, faithful to the full
+   alternate-screen render) and embedded with `asciinema-player`. The same
+   casts are reused inline in the docs — one recording format serves both
+   the landing page and documentation enrichment. Recordings are produced by
+   a **scripted-input driver** that types commands into a real PTY with
+   viewer-friendly pacing; the app's own `history.log` **replay** (ADR-0034)
+   re-executes commands without typing animation or pacing and is therefore
+   suitable only for state-deterministic docs snippets, not the hero demo.
+
+3. **In-page WASM playground — deferred** (OOS: **deferred**, not rejected).
+   A live, type-it-yourself playground compiled from the Rust app to
+   WebAssembly is desirable but is a multi-week sub-project, so it does not
+   block the site. The demo section is designed with a stable seam (a single
+   `Demo` component contract) so a WASM playground island can replace the
+   asciinema player later with no change to call sites. Recorded boundary
+   for that future work:
+   - **Portable core (runs on `wasm32-unknown-unknown` largely as-is):**
+     `src/dsl/*` (parser, types, grammar, walker), the pure `App::update()`,
+     `ui.rs`, `theme.rs`, `friendly/*`, output rendering; an in-memory DB
+     path already exists (`Connection::open_in_memory()`). `rusqlite`
+     compiles to the browser target via its `ffi-sqlite-wasm-rs` feature.
+   - **Native edge needing `cfg`-gated browser replacements:** the
+     multi-thread Tokio runtime + the dedicated DB **worker thread**
+     (ADR-0010) → current-thread/in-line async; `crossterm` terminal +
+     event-stream → a browser backend (e.g. Ratzilla's DOM/Canvas) + DOM
+     events; `arboard`, `zip`, file persistence (ADR-0015), file logging;
+     and the rusqlite **backup-API** undo (ADR-0006) → a SQL dump/restore.
+   When taken up, this becomes its own ADR + iteration plan.
+
+4. **Hosting — portable static build; Vercel is the likely target.** Astro 6
+   builds to static HTML/CSS with no adapter, so the output deploys equally
+   to Vercel, Cloudflare Pages, Netlify, or GitHub Pages. We avoid coupling
+   to any one host. **No CI yet** — the site is tested locally (`pnpm dev` /
+   `pnpm build`) until the repo reaches its public home.
+
+5. **Repo topology — monorepo.** The site lives under `website/` in the
+   playground repo; the crate stays at the repo root. The repo as a whole
+   moves to its public home later; site and crate travel together.
+
+6. **Canonical docs home — the website.** User-facing documentation lives on
+   the site. In-repo `docs/` keeps ADRs, handoffs, and development notes;
+   `docs/simple-mode-limitations.md` (requirement DOC1) was a development aid
+   and now *feeds* the site's content rather than competing with it. The
+   sharing recipes promised by requirement E2 become a docs page.
+
+7. **Documentation scope and conventions.** Document the **full supported
+   feature set**. Any capability not yet fully implemented (a small minority
+   — e.g. multi-line input, query cancellation, `seed`, `m:n` convenience,
+   ER-diagram export, the `show tables`/`relationships`/`indexes` family) is
+   either omitted or carries a clear **"planned / not yet available"**
+   callout — never presented as shipped. Two wording rules bind all
+   user-facing copy:
+   - **No engine name** (SQLite/STRICT/rusqlite/PRAGMA) — continues the
+     user-facing posture of ADR-0002; copy says "the database"/"the engine".
+   - **No "DSL"** — it is internal jargon. The two input modes are **simple
+     mode** (the playground's keyword command language) and **advanced
+     mode** (SQL).
+
+8. **Install documentation — two mechanisms.** The install page documents
+   **prebuilt release binaries** (self-hosted download — not GitHub
+   Releases, since the repo will move) and **package managers**. Both can be
+   written now against the planned mechanisms; concrete download URLs slot in
+   at release. (Distribution items D1–D3 in `requirements.md` remain the
+   tracking home for the release tooling itself.)
+
+## Consequences
+
+- The site can ship on the strength of already-implemented features; it is
+  gated on writing and recording, not on finishing the app.
+- One recording format (asciinema `.cast`) serves both marketing and docs,
+  and is reusable as the app evolves (re-run the script, re-record).
+- The WASM playground is preserved as a real future option without holding
+  up launch; the demo seam keeps the upgrade cheap.
+- A single canonical docs home removes the divergence risk of maintaining
+  user docs in two places.
+- Website build choices (Decisions 1, 2, 4, 5) are recorded here for
+  traceability but do not, by themselves, warrant further ADRs; only
+  app-architecture decisions (notably the future WASM port) will.
+
+## Out of scope
+
+- **In-page WASM playground** — *deferred* (see Decision 3); revisit as its
+  own ADR + iteration plan.
+- **Hosted/SaaS playground or a server-backed doc CMS** — *rejected*: a
+  static site fully satisfies the need, consistent with ADR-0007's
+  no-hosted-publishing stance. Revisit only if real demand emerges.

docs/website/adr/README.md

@@ -0,0 +1,19 @@
+# Website Architecture Decision Records
+
+Decision records for the **public website + documentation site** subproject
+(the Astro/Starlight site under `website/`). These are kept in their own
+namespace, separate from the project-wide ADRs in
+[`docs/adr/`](../../adr/README.md), so website decisions never compete with
+the main global ADR sequence for numbers — see
+[ADR-0000 "Numbering discipline"](../../adr/0000-record-architecture-decisions.md).
+
+**Numbering.** Files are named `<date>-adr-website-<NNN>.md` and referenced
+in prose as `ADR-website-NNN`. The `<date>` (the ADR's accepted/created day,
+`YYYYMMDD`) plus the `website` segment keeps the namespace disjoint from
+`main`'s integers. Assign the next free `NNN` from this index. Every ADR
+change updates this index in the same edit (the ADR-0000 index-upkeep rule
+applies here too).
+
+## Index
+
+- [ADR-website-001 — Public website and documentation site](20260604-adr-website-001.md) — **Accepted 2026-06-04** (formerly ADR-0044 in the main index; moved here 2026-06-10 to end recurring cross-branch number collisions). The first public website: a marketing landing page plus the **canonical** user docs. Stack **Astro 6 + Starlight + Tailwind v4** (chosen over SvelteKit + Tailwind for a docs-heavy + marketing site; interactive bits as Astro islands). Showcase demos are **asciinema** `.cast` recordings (scripted-input driver for paced, re-recordable sessions — *not* `history.log` replay), reused inline in docs. The **in-page WASM playground is deferred** (OOS: deferred) behind a stable `Demo` seam, with the portable-core vs native-edge boundary recorded for a future ADR + iteration plan. Portable **static build** (Vercel target, but host-agnostic); **no CI yet**; **monorepo** (`website/`). Docs cover the **full supported feature set** with "planned" callouts for the unshipped minority; two wording rules bind user-facing copy — **no engine name** (continues ADR-0002) and **no "DSL"** ("simple mode" / "advanced mode"). Install docs cover **prebuilt binaries + package managers** (D1–D3 track the release tooling). Plan: [`docs/website/plans/20260604-website-implementation-plan.md`](../plans/20260604-website-implementation-plan.md)

docs/website/plans/20260604-website-implementation-plan.md

@@ -0,0 +1,198 @@
+# Plan: public website and documentation site
+
+**Date:** 2026-06-04 · **Status:** ready to build
+
+Decisions for this work are recorded in
+[ADR-website-001](../adr/20260604-adr-website-001.md): Astro 6 +
+Starlight + Tailwind v4; asciinema demos reusable in docs; the in-page WASM
+playground deferred behind a stable demo seam; portable static hosting
+(Vercel target); monorepo (`website/`); website is the canonical docs home;
+full-feature-set docs with "planned" callouts; install docs cover prebuilt
+binaries + package managers. This plan is the *how*.
+
+## Repository layout
+
+The site lives under `website/` in this repo; the crate stays at the root.
+
+```
+website/
+├── package.json              # pnpm; astro, @astrojs/starlight, tailwind v4
+├── astro.config.mjs          # Starlight integration + sidebar nav
+├── src/
+│   ├── pages/index.astro     # marketing landing (custom, not Starlight)
+│   ├── components/
+│   │   ├── Demo.astro        # demo SLOT — the WASM-playground seam
+│   │   └── Cast.astro        # asciinema-player island wrapper
+│   ├── content/docs/         # Starlight MDX docs (the bulk of the work)
+│   └── styles/               # shared Tailwind + Starlight theme tokens
+├── public/casts/             # recorded *.cast asciinema files
+├── README.md                 # local dev + recording recipe
+└── STYLE.md                   # living documentation style guide
+```
+
+Root `.gitignore` gains `website/node_modules`, `website/dist`,
+`website/.astro`.
+
+## Documentation inventory (grounded — drives Phase D scope)
+
+Built from `docs/handoff/55–59`, `docs/adr/*`, the command REGISTRY
+(`src/dsl/grammar/mod.rs:603`, which also auto-assembles in-app `help`), the
+`Command` enum (`src/dsl/command.rs:149`), and
+`src/friendly/strings/en-US.yaml` — **not** the coarse `requirements.md`
+checkboxes (handoff-59 found those ~46% mis-marked; they now use a `[/]`
+"partial" legend — trust the code, not the marker). Refreshed **2026-06-09
+after merging `main`**, which added the show-list/detail, `help <command>`,
+and compound-PK FK surface (see the dedicated bullet below). Test state:
+**2193 passing, 0 failing, 1 ignored.**
+
+**SHIPPED — document as-is (the doc core):**
+- Input modes: simple, advanced (SQL), `:` one-shot escape, `mode` command,
+  per-project mode restore (ADR-0003/0015/0037).
+- Full simple-mode command surface: create/drop table; add/drop/rename/
+  change column; add/drop 1:n relationship (named, ON DELETE/UPDATE
+  CASCADE/SET NULL/RESTRICT, `--create-fk`); add/drop index; insert/update/
+  delete (required WHERE + `--all-rows`; complex WHERE: AND/OR/NOT, LIKE,
+  IS NULL, IN, BETWEEN); show table/data (where/limit); add/drop constraint;
+  explain (ADR-0009/0013/0014/0025/0026/0028/0029).
+- Full advanced-mode SQL: CREATE/DROP/ALTER TABLE (cols, constraints, inline
+  + table FKs, rename, alter-column-type), CREATE [UNIQUE]/DROP INDEX; SELECT
+  (joins, GROUP BY/HAVING, ORDER BY, LIMIT/OFFSET, UNION/INTERSECT/EXCEPT,
+  WITH [RECURSIVE] CTEs); INSERT (multi-row, ON CONFLICT, RETURNING)/UPDATE/
+  DELETE; full expression grammar incl. CASE, CAST, curated functions;
+  EXPLAIN over SQL (ADR-0030–0039).
+- Types: all ten, advanced-mode SQL aliases, serial/shortid auto-fill
+  (ADR-0005/0011/0017/0018). Constraints: PK incl. compound, NOT NULL,
+  UNIQUE, CHECK, DEFAULT, FK (ADR-0029/0013/0035).
+- Undo/redo, history.log journal, replay, `--resume`, `--no-undo`
+  (ADR-0006/0034). Projects & storage: project.yaml + CSV + history.log,
+  save/save as/load/new/rebuild, temp projects, `--data-dir`
+  (ADR-0004/0015). Export/import (zip), clipboard copy/copy all/copy last
+  (ADR-0007/0041).
+- Friendly errors (all five categories) + validity indicator
+  (ADR-0019/0027), DSL→SQL teaching echo (ADR-0038), EXPLAIN plan tree
+  (ADR-0028), box-drawing tables (ADR-0016), tab completion + syntax
+  highlighting + in-line editing (ADR-0022).
+- **Added by the `main` merge (2026-06-09):** schema-inspection commands
+  `show tables` / `show relationships` / `show indexes` and the singular
+  `show relationship <name>` / `show index <name>` detail views (V5/V5a);
+  `help [<command>]` per-command detail + `help types` + general reference
+  (H3); **compound-primary-key foreign-key references** — DSL
+  `from <P>.(a, b) to <C>.(x, y)` and SQL `FOREIGN KEY (a, b) REFERENCES
+  P(x, y)` (single-column form unchanged) (ADR-0043, T3); friendlier
+  parse-error near-miss messaging (H1a, ADR-0042). These need coverage: a
+  schema-inspection page (the `show` family) and compound-FK examples on the
+  Relationships page.
+
+**DOCUMENT WITH CAVEAT:** `add unique index` is advanced-only; simple-mode
+table rename is intentionally absent (rename is `ALTER TABLE … RENAME TO`);
+`hint` (H2) is still partial; a compound-FK *violation* message names only
+the first column pair (enforcement is correct — a messaging-only residual).
+
+**OMIT or MARK "planned":** multi-line input (I1), readline shortcuts (I1b),
+in-flight cancellation / query timeout (I5/B3), `seed` (SD1), `m:n`
+convenience (C4), one-step modify relationship (C3a), relationship line-art
+(V1), ER-diagram export (V3), session-log + Markdown export (V4).
+
+**Mine verbatim for docs:** `en-US.yaml` `help.app.*`, `help.ddl.*`,
+`help.data.*`, `help.types_reference`, `parse.usage.*` (one-line syntax
+templates), `hint.*` — keeps docs and in-app help consistent.
+
+## Phases
+
+### A — Scaffold
+`pnpm create astro@latest` (Starlight template) in `website/`; `astro add
+tailwind` (Tailwind v4 via `@tailwindcss/vite`); add
+`@astrojs/starlight-tailwind`. Confirm `pnpm dev` serves and `pnpm build`
+emits a static `dist/`. Echo build steps for traceability.
+
+### B — Landing page
+Custom `src/pages/index.astro` (Starlight owns `/docs/*`). Hero + value prop
+("learn relational databases by doing"), feature highlights from the
+inventory, an embedded demo cast above the fold. Use the `frontend-design`
+skill to avoid generic AI aesthetics; honour NFR-4/5/7 (distinctive design,
+meaningful colour, light/dark).
+
+### C — asciinema recording workflow
+Record real `rdbms-playground` sessions to `public/casts/*.cast` using a
+**scripted-input driver** (e.g. `asciinema-automation`/autocast, or an
+expect/doitlive script) for paced, re-recordable demos. Record at a fixed
+sensible cols×rows; provide light + dark player themes. `Cast.astro` wraps
+`asciinema-player` as a `client:visible` island; the same component embeds
+casts inline in docs. Document the recipe in `website/README.md`.
+(`asciinema` 2.4.0 is installed.)
+
+### D — Documentation (the bulk)
+**Five** top-level sidebar sections (autogenerated per directory). The key
+split: *Using the playground* = the application you drive; *Reference* = the
+database language you build with.
+- **Getting started** — install (prebuilt binaries + package managers),
+  first project, simple vs. advanced mode, the example library.
+- **Using the playground** — command-line options; the assistive editor
+  (completion, syntax highlighting, the `[ERR]`/`[WRN]` validity indicator,
+  hints, in-line editing); the output pane (PageUp/PageDown scrolling — the
+  fuller V4 session-log / Markdown export is *planned*, mark it); projects
+  (save / load / new / rebuild); undo, redo & history (+ replay); export &
+  import (E2 recipes); copy to clipboard; getting help (`help` /
+  `help <command>` / `hint`). (ADR-0003 "app-level commands" + ADR-0022/0027
+  typing assistance + the CLI.)
+- **Guides** — task walkthroughs.
+- **Reference** — the database language: Tables, Columns, Relationships,
+  Indexes, Constraints, Inserting & editing data, Querying & inspecting
+  (`show` / `select`), Types, Query plans (EXPLAIN), Errors explained, the
+  simple-command → SQL teaching echo.
+- **Concepts** — the *why*: projects & storage model, the derived database,
+  how undo works.
+
+**Surface the assistive editor prominently** — it is a differentiator and
+most helps beginners: a landing-page card + a Getting-started mention, both
+linking into *Using the playground*. It is prime asciinema-cast material
+(completion / validity indicator are motion a still code block can't show).
+
+Build order: Tier 1 simple-mode reference + types + constraints + input
+modes + mined help/usage strings → Tier 2 advanced SQL + relationships +
+project lifecycle + undo/history → Tier 3 teaching echo + EXPLAIN + errors +
+completion/highlighting → Tier 4 clipboard + hints + editing.
+
+Conventions live in the **living style guide** `website/STYLE.md` (binding
+rules from ADR-website-001 §7 — no engine name, **no "DSL"**, "planned" callouts —
+plus finer conventions and an open-decisions log for depth/splitting/example
+dataset/etc. as they settle). Sources to mine: `src/dsl/command.rs`,
+`src/dsl/grammar/*`, the REGISTRY, `en-US.yaml`, `docs/adr/*`,
+`docs/simple-mode-limitations.md`.
+
+### E — Hosting & portability
+Keep the default static build (no adapter); `dist/` deploys to Vercel or any
+static host. `website/README.md` notes the Vercel preset (root dir
+`website/`) and the one-line `@astrojs/vercel` switch if SSR is ever needed.
+
+## Demo seam (WASM hook)
+
+`Demo.astro` exposes a stable contract (`{ src, title, height, autoplay }`).
+At launch it renders `Cast.astro`; later a `Playground.astro` WASM island
+swaps in behind the same props on the landing page and in docs, with zero
+call-site changes. Boundary details are in ADR-website-001 §3.
+
+## Verification
+
+- `pnpm dev` renders landing + docs; `pnpm build` emits a clean static
+  `dist/` with no errors/warnings.
+- Landing shows at least one playing `.cast`; the same component renders a
+  cast inline in a docs page (proves reuse).
+- Starlight link-check passes (broken internal links fail the build).
+- Docs grep clean of forbidden terms: **no "DSL"**, no engine name.
+- A `dist/` static deploy works on Vercel (manual import) — confirms
+  portability. (No CI gate yet, per ADR-website-001 §4.)
+
+## Notes / recommendations (non-blocking)
+
+- **Doc drift:** consider generating the command reference from source (the
+  `help` REGISTRY / `en-US.yaml`) rather than hand-writing all of it.
+- **Accessibility/SEO:** pair each hero `.cast` with a text transcript or the
+  equivalent docs snippet.
+- **Branding/domain & analytics** unspecified — assume none until decided;
+  no third-party trackers without consent.
+- Tailwind v4 + Starlight have occasional theme-token friction; the
+  `@astrojs/starlight-tailwind` plugin is the supported bridge.
+- Starlight ships local search (Pagefind) by default.
+- No `README.md` exists at the repo root yet — wanted for the destination
+  repo; out of this plan's core scope but flagged.