feat(#777): register Cursor-native hooks (.cursor/hooks.json) for session-start/post-tool parity (#831)

* feat(#777): register Cursor-native hooks (.cursor/hooks.json) for session-start/post-tool parity

- Add gsd-cursor-session-start.js: injects STATE.md presence reminder (or
  new-project nudge) into Cursor sessions via the sessionStart hook event
- Add gsd-cursor-post-tool.js: emits an additional_context nudge when
  write-class tool calls touch .planning/ files (postToolUse hook event)
- Add 'cursor-hooks-json' installSurface to runtime-config-adapter-registry;
  writeCursorHooksJson/reconcileCursorHooksJson write the canonical
  { version: 1, hooks: { sessionStart, postToolUse } } JSON shape with
  idempotent reconciliation that preserves user-owned hook entries
- Hook scripts are copied with /gsd:→gsd- rewrite so installed files
  contain no colon-form slash-command refs (bug-376 invariant)
- 20 new tests in tests/cursor-hooks.test.cjs cover all reconciler paths,
  entry helpers, removal, runtime adapter surface, and hook script behavior
- Update CONTEXT.md, ARCHITECTURE.md, installer-migrations.md, and
  000-first-time-baseline.cts to include Cursor hooks.json surface

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

* fix(#777): build hooks/dist on demand in bug-376 test for scoped/windows CI

hooks/dist is gitignored and only produced by `npm run build:hooks`.
The CI scoped (ubuntu-latest/node-22) and windows (windows-latest/node-24)
test jobs do NOT run build:hooks before executing tests, so bug-376's
prerequisite suite was failing with "hooks/dist not found" on both legs.

Add ensureHooksDist() helper (mirrors bug-3357 pattern) that builds
hooks/dist on demand in the before() hooks of prerequisite and Suite 3.
Also add ensureHooksDist() call to Suite 3's before() so the snapshot
step is also hermetic.

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

---------

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

docs/ARCHITECTURE.md

@@ -802,7 +802,7 @@ The migration-specific ownership and source snapshots live in
 | Codex | `~/.codex` | `./.codex` | `skills/gsd-*/SKILL.md` | `agents/` source markdown plus per-agent TOML | `config.toml` `[agents.gsd-*]`, `[features].hooks` (canonical; legacy alias `codex_hooks` is recognized and migrated forward on reinstall, #3566), and hook tables |
 | GitHub Copilot | `~/.copilot` | `./.github` | `skills/gsd-*/SKILL.md`, `copilot-instructions.md`, and `AGENTS.md` (repo root, local) | `.agent.md` files | Self-contained `sessionStart` hook (`hooks/gsd-session.json`, inline `command` type); no statusline |
 | Antigravity | auto-detected: `~/.gemini/antigravity`, `~/.gemini/antigravity-ide`, or `~/.gemini/antigravity-cli` | `./.agent` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | Gemini-style `settings.json` hook entries when installed by GSD |
-| Cursor | `~/.cursor` | `./.cursor` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | Rule references under `rules/`; no GSD hooks |
+| Cursor | `~/.cursor` | `./.cursor` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | Rule references under `rules/`; `hooks.json` with sessionStart context injection and postToolUse STATE.md monitor (#777) |
 | Windsurf | `~/.codeium/windsurf` | `./.windsurf` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | Rule references under `rules/`; no GSD hooks |
 | Augment Code | `~/.augment` | `./.augment` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | No GSD hooks or statusline |
 | Trae | `~/.trae` | `./.trae` | `skills/gsd-*/SKILL.md` | `agents/gsd-*.md` | Rule references under `rules/`; no GSD hooks |