chore(#2143): markdown table model + schema registry + fail-loud pilot — Phase 1 (#2248)

* chore(#2143): markdown table model + schema registry + fail-loud pilot — Phase 1

Phase 1 of epic #2143 (ADR-2143): consolidate markdown table parsing onto a
canonical seam and migrate the pilot reader.

- Add src/markdown-table.cts: parseMarkdownTable (GFM tables -> typed
  {columns, rows} addressed by column NAME; ragged rows are typed parse
  errors, not silent), a single-source TABLE_SCHEMAS registry
  (RoadmapProgress / RequirementsTraceability / QuickTasks / Security, with
  variants under one id), matchTableSchema, and findTableBySchema. Result<T>
  is scoped to this seam (distinct from the dispatch Result).
- Migrate deriveProgressFromRoadmap (src/phase-lifecycle.cts) off the
  position-anchored regex to name-based resolution via the seam — fixes #2137
  (the 5-column milestone-grouped Progress table previously returned all-null).
- Add a schema-backed `gsd-tools quick-tasks-append` subcommand and route
  fast.md's log_to_state through it, retiring the inline `awk NF-2` column
  arithmetic — fixes #2133 (addresses #2012, #2119). Cell values are escaped
  (| and newlines) and the STATE.md read-modify-write is atomic under
  readModifyWriteStateMd (lost-update race, cf. #500/#905/#1230).
- Writer/reader/template parity test guards TABLE_SCHEMAS against drift
  (ADR-2143 §3 Generative-Fix-Divergence).

Registration: .gitignore, eslint.config.mjs, docs/INVENTORY.md +
INVENTORY-MANIFEST.json, CONTEXT.md glossary, docs/CLI-TOOLS.md.

Behaviour-preserving for the canonical 4-column Progress table; the named
bugs are driven fail-first. Extend-never-mutate (ADR-2143 §2).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* chore(#2242): backfill changeset PR number (#2248)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(#2242): escape backslash before pipe in markdown-table cell escaping

CodeQL js/incomplete-sanitization (high): escapeCell escaped | -> \| but not
the backslash itself. Now escapes \ -> \\ before | -> \|, and splitTableRow
unescapes both \\ -> \ and \| -> | symmetrically so cell values (incl.
literal backslashes) round-trip exactly. Added backslash round-trip tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* fix(#2242): read ROADMAP Progress table by column name — supersede #2168 ad-hoc scan

Rebase reconciliation with #2168 (the tactical #2137 fix that marked itself
"pending #2143"). deriveProgressFromRoadmap now resolves the Progress table via
a new seam helper findTableWithColumns (first table whose header is a superset of
Phase/Plans Complete/Status/Completed, any order, extra columns ignored) and reads
cells by NAME — order/injection-invariant per ADR-2143 §3 — instead of the exact
TABLE_SCHEMAS match. This satisfies #2168's column-invariance property test while
staying seam-based and preserving its `## Progress` scoping (#2012/#1445).
Ragged Progress tables now resolve to null (ADR-2143 fail-loud); updated the stale
state.test.cjs assertion that predated the Phase-1 migration.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

eslint.config.mjs

@@ -213,6 +213,8 @@ export default tseslint.config(
       'gsd-core/bin/lib/teams-status.cjs',
       // ADR-1372: tsc-generated runtime artifact — lint the src/markdown-sectionizer.cts source.
       'gsd-core/bin/lib/markdown-sectionizer.cjs',
+      // ADR-2143: tsc-generated runtime artifact — lint the src/markdown-table.cts source.
+      'gsd-core/bin/lib/markdown-table.cjs',
       // ADR-1239 Phase C-1 (#1680): tsc-generated — lint src/embedding-adapter.cts + src/adapter-declarative.cts.
       'gsd-core/bin/lib/embedding-adapter.cjs',
       'gsd-core/bin/lib/adapter-declarative.cjs',