walker+completion: surface list trailing-optionals + identifiers-first ordering (ADR-0022 Amendment 2)

walk_repeated discarded the last matched item's trailing-optional
expectations at a clean item boundary, so a comma-separated list
offered no continuation after a complete item: `order by Name `
gave no asc/desc, `select Name ` no `as`, `create table …
Code(text) ` no not/unique/default/check. Capture the last item's
skipped set and surface it when the list ends at an item boundary
(the separator `,` itself is deliberately not surfaced).

That fix made expression-position candidate lists long, which
exposed a visibility problem: the hint panel's candidate line is
single-row and window-scrolls on overflow, centring on item 0 when
nothing is selected — so with keywords-first, schema identifiers
scrolled off behind the `>` marker. Reverse the ordering: schema
identifiers (table/column/relationship names) now sort before
keywords, since a name the user would have to look up is the
highest-value completion and must stay visible (keywords are
learned over time; the tok_identifier/tok_keyword colour split
marks the boundary). This reverses the handoff-14 keywords-first
call, now recorded in ADR-0022 Amendment 2.

Tests: walker expected-set + completion-layer regressions for the
trailing-optionals and the ordering; candidate_ordering.rs header
invariant inverted; ~20 typing-surface snapshots re-baselined; a
two-line hint box recorded as a deferred follow-up.

docs/adr/README.md

@@ -27,7 +27,7 @@ This directory contains the project's ADRs, recorded per
 - [ADR-0019 — Friendly error layer (H1) and i18n message catalog](0019-friendly-error-layer-and-i18n.md)
 - [ADR-0020 — Tokenization layer for the DSL parser](0020-tokenization-layer-for-the-dsl-parser.md)
 - [ADR-0021 — Parser-as-source-of-truth for H1a (per-command usage in parse errors)](0021-parser-as-source-of-truth-for-h1a.md)
-- [ADR-0022 — Ambient typing assistance: colour, hint panel, completion (I3 + I4)](0022-ambient-typing-assistance.md) — **Amendment 1 supersedes §12's simple-mode-only carve-out**: the unified mode-aware walker (ADR-0030/0031/0032) now speaks SQL, so advanced-mode ambient assistance is re-enabled. `ambient_hint_in_mode` + `hint_resolution_at_input_in_mode` + `expected_for_hint_snapshot` thread `Mode`; `render_hint_panel` calls ambient for all modes (no more advanced-mode `None`); the one-shot `:` sigil is stripped before the ambient walk. Fixes a live bug where advanced-mode SQL hinting/completion-preview were dead despite Phase 2 marking them green (validated at the engine layer, not the UI). Simple-mode gating, highlighting, and the §13 performance posture are unchanged; covered by an app-level render test plus ambient-layer regression locks
+- [ADR-0022 — Ambient typing assistance: colour, hint panel, completion (I3 + I4)](0022-ambient-typing-assistance.md) — **Amendment 1 supersedes §12's simple-mode-only carve-out**: the unified mode-aware walker (ADR-0030/0031/0032) now speaks SQL, so advanced-mode ambient assistance is re-enabled. `ambient_hint_in_mode` + `hint_resolution_at_input_in_mode` + `expected_for_hint_snapshot` thread `Mode`; `render_hint_panel` calls ambient for all modes (no more advanced-mode `None`); the one-shot `:` sigil is stripped before the ambient walk. Fixes a live bug where advanced-mode SQL hinting/completion-preview were dead despite Phase 2 marking them green (validated at the engine layer, not the UI). Simple-mode gating, highlighting, and the §13 performance posture are unchanged; covered by an app-level render test plus ambient-layer regression locks; **Amendment 2 reverses the handoff-14 keywords-first candidate ordering** — schema identifiers (table/column/relationship names) now sort *before* keywords so a name the user would have to look up stays visible in the single-row, window-scrolled candidate line (keywords are learned over time; the `tok_identifier`/`tok_keyword` colour split marks the boundary); shipped with a `walk_repeated` fix that surfaces a list item's trailing optionals at a clean boundary (`order by Name ` → `asc`/`desc`, `select Name ` → `as`, `create table … Code(text) ` → `not`/`unique`/`default`/`check`; the `,` separator deliberately not surfaced); records a deferred two-line hint box for growing lists
 - [ADR-0023 — Unified declarative grammar tree](0023-unified-grammar-tree.md) — direction (superseded for execution detail by ADR-0024)
 - [ADR-0024 — Unified grammar tree: execution plan](0024-unified-grammar-tree-execution-plan.md) — **Accepted**, the executable spec — implemented (Phases A–F; Phase F shipped "minimal", `parser.rs` retained as the router — see the ADR's Phase F implementation note)
 - [ADR-0025 — Indexes](0025-indexes.md) — **Accepted**, `add index` / `drop index`, persistence, rebuild-table preservation, and items-list display (`C3` index portion + `S2`)