docs: ADR-0048 Phase 2 implemented + handoff 66

- ADR-0048: status → Phase 1 + Phase 2 implemented; D2 amendment
  (quoted dates, no date-literal token) and the override × UNIQUE
  capacity-guard decision; phasing/Status blocks marked done.
- README index: 0048 entry updated (Phase 2 shipped, 2400 tests).
- requirements.md: SD2 → [x] (the override-hooks core + column-fill).
- handoff 66: this session's Phase 2 build + the two /runda passes.

docs/handoff/20260611-handoff-66.md

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+# Session handoff — 2026-06-11 (66)
+
+Sixty-sixth handover. Continues from handoff-65 (ADR-0048 `seed`
+Phase 1). This session built **ADR-0048 Phase 2** end to end: the
+**`set` override clause** (D2) and the **`<table>.<column>`
+column-fill** form (D1 form 2) — the two surfaces Phase 1 deliberately
+deferred. Designed-then-DA-vetted (a `/runda` pass that caught a real
+ADR-vs-grammar conflict), then built test-first.
+
+## §1. State at handoff
+
+**Branch:** `main`. All Phase-2 work is in the working tree;
+**commits are pending the user's approval** (see §6). Unpushed is the
+normal working state.
+
+**Tests: 2400 passing / 0 failing / 0 skipped / 1 ignored** (the
+long-standing `friendly` doctest). **Clippy clean** (nursery, all
+targets). +42 over handoff-65's 2358.
+
+## §2. What landed (read ADR-0048 — Status + D1/D2/D9/D13)
+
+`seed <T>[.<col>] [count] [set <overrides>] [--seed <n>]`.
+
+- **`set` override clause (D2):** four forms, comma-separated —
+  `status = 'active'` (fixed), `role in ('a','b')` (pick-list),
+  `work_addr as email` (named generator), `price between 10 and 100`
+  (range; numeric **and quoted dates**). Type-aware; an override
+  **drops its column from the generic-fill advisory** (D13). Value
+  slots reuse `update`'s typed `current_column_value` (quoting
+  enforced structurally — a bare word is rejected).
+- **Column-fill (D1 form 2):** `seed users.email [set …]` fills one
+  column across **existing** rows (an UPDATE). Refuses PK / autogen
+  (`serial`/`shortid`/`blob`) targets; **empty table → friendly
+  no-op**; FK target samples the parent; UNIQUE/identifier target gets
+  collision-free values; **one undo step**; `set` may only adjust the
+  filled column; a row count is refused.
+- **Named-generator vocabulary (D9):** `src/seed/vocabulary.rs` —
+  `KNOWN_GENERATORS` + `generator_for_name` + `is_known_generator_prefix`,
+  the single source of truth for completion, validity, and the executor.
+- **Range generator:** `Generator::Range { low, high }` in
+  `src/seed/generators.rs`, interpreted per destination type;
+  `range_bounds_reason` validates compatibility before generation.
+- **Ambient wiring:** completion (generator names after `as`, the
+  `set <col>` and `.col` column slots, the `set` keyword); highlight
+  (new `HighlightClass::Function` → existing `tok_function`); validity
+  (new `IdentSource::Generators` — unknown generator flagged `[ERR]`;
+  unknown column in `set`/`.col` flagged via the existing Columns
+  path); help (`help.data.seed`); parse-error pedagogy near-miss rows;
+  the D13 advisory's **Phase-2/3 wording** (points at `set` and the
+  column-fill repair). Both modes (D5).
+
+## §3. The ADR amendment (a real DA find)
+
+The pre-build `/runda` pass found that **ADR-0048 D2's "dates stay
+unquoted" was impossible** — this DSL has **no date-literal token**
+(`Value` is `Number`/`Text`; dates are quoted strings validated by
+`bind_date`). Escalated to the user, who chose **quoted dates +
+amend the ADR** (the grammar-consistent option). D2 now carries a
+dated amendment; the range form uses `between '2023-01-01' and
+'2024-12-31'`. This was the only divergence from the ADR text; numbers
+remain unquoted.
+
+## §4. Where the code lives
+
+- **`src/dsl/command.rs`** — `Command::Seed` gains `target_column:
+  Option<String>` + `overrides: Vec<SeedOverride>`; new `SeedOverride`
+  / `SeedOverrideKind`.
+- **`src/dsl/grammar/data.rs`** — `SEED_SET_CLAUSE` + `SEED_DOT_COLUMN`
+  grammar; `SEED_GENERATOR` slot (`IdentSource::Generators`,
+  `HighlightClass::Function`); `build_seed` + the override fold
+  (`build_seed_overrides` / `parse_seed_override_tail`).
+- **`src/dsl/grammar/mod.rs`** — `IdentSource::Generators` +
+  `HighlightClass::Function`.
+- **`src/db.rs`** — `apply_seed_overrides` / `seed_override_plan` /
+  `seed_override_literal`; `do_seed_column_fill`; `do_seed` +
+  `Database::seed` + worker wiring threaded with the new params.
+- **`src/seed/`** — `vocabulary.rs` (new); `generators.rs` (range
+  generator + `range_bounds_reason`); `mod.rs` (`Generator::Range`).
+- **`src/completion.rs`** — generator candidates after `as`; generator
+  validity. **`src/input_render.rs`** — `"generator"` invalid-ident
+  kind. **`src/theme.rs`** — `Function → tok_function`.
+- **Catalog** — `help.data.seed`, `parse.usage.seed`,
+  `seed.advisory_generic` (Phase-2/3 wording) in `en-US.yaml`;
+  `keys.rs` placeholders updated.
+- **Tests** — `tests/it/seed.rs` (+~30: builder fold, executor
+  set/column-fill, undo, advanced mode), `src/seed/{vocabulary,
+  generators}.rs` (range + vocabulary units), `src/completion.rs`
+  (generator + column validity), `src/dsl/walker/highlight.rs`,
+  `tests/typing_surface/mod.rs` (completion slots),
+  `tests/it/parse_error_pedagogy.rs` (near-miss rows).
+
+## §5. Two implementation refinements vs. the ADR (both met the contract)
+
+- **Quoted dates** (the D2 amendment, §3).
+- **Value slots reuse `current_column_value`** (the `update … set`
+  typed slot) rather than the raw ADR-0026 expression operand — no
+  spurious column-ref match, typed narrowing, consistent with
+  `update`. The user-facing contract (quoted literals, type-aware) is
+  fully met.
+
+The `seed_take_value` / `seed_set_error` builder paths are
+drift-guards (the typed slots only ever match value literals, so a bare
+word is rejected at the grammar level) — they use the generic
+`parse.error_wrapper`, mirroring `expr::build_expr`.
+
+## §6. How to take over / next steps
+
+1. Read handoffs 64 → 65 → 66, `CLAUDE.md`, `docs/requirements.md`,
+   `docs/adr/0048-…md` (Status block + D1/D2/D9/D13 + the amendment).
+2. **Seed is feature-complete (SD1 + SD2).** `requirements.md`: **SD1
+   `[x]`, SD2 `[x]`**. The only open A1 gap is `hint`/**H2** (own ADR).
+3. **Commits pending approval.** Suggested split:
+   - `feat(seed): set override clause + column-fill (ADR-0048 Phase 2)`
+     — all `src/` + `tests/` changes.
+   - `docs: ADR-0048 Phase 2 implemented + handoff 66` — ADR / README /
+     requirements / this file.
+4. Next options (user's call): **H2 `hint`** (closes A1); **TT5 CI**;
+   the larger **V4 journal** / **tutorial** ADRs; or Tier-4 PTY (TT4).
+5. Consider a `cargo sweep` at this milestone (`target/` grows).
+
+## §7. Post-implementation `/runda` pass (done this session)
+
+A DA pass over the completed code found **no correctness bugs and no
+dropped requirements**; all D1–D18 acceptance criteria verified met,
+tests confirmed to catch regressions. One **design fork** was surfaced
+and **resolved by the user**:
+
+- **Bounded override × UNIQUE column** — a fixed value / too-short
+  pick-list on a single-column-UNIQUE target used to silently cap the
+  run (e.g. `seed users 100 set email = 'x'` → 1 row). Now a **friendly
+  error** up front (`seed_override_capacity_guard`, `src/db.rs`), for
+  both whole-row and column-fill; generators/ranges stay cap-based
+  (unbounded sources). ADR-0048 D2 documents it; two tests pin it.
+
+Remaining **non-blocking** edges (noted, not bugs):
+
+- Overriding an **FK column** with a literal: the override wins (D2); a
+  non-parent value fails safely through the FK-error layer.
+- **Column-fill of one column of a *compound* FK** samples that column
+  independently → an invalid tuple fails safely (UPDATE rejected,
+  rollback), never corrupts. Single-column FKs / non-FK columns are
+  exact.
+- The generator slot uses the **default candidate-ladder hint** (offers
+  the vocabulary), not a dedicated prose intro — discoverability is met
+  by completion; a prose intro is optional polish.