feat(phase-plans): extract shared scanPhasePlans helper (k014) (#3308)

* test(phase-plans): red — shared scanPhasePlans contract + parity across call sites (#3262)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* feat(phase-plans): extract shared scanPhasePlans helper (k014) (#3262)

Eliminates four divergent copies of the plan-scan algorithm:
- roadmap.cjs:countPhasePlansAndSummaries (root call site)
- state.cjs:buildStateFrontmatter (1 of 3)
- state.cjs:cmdStateValidate (2 of 3)
- state.cjs:cmdStateSync (3 of 3)
- init.cjs:listPhasePlanFiles / listPhaseSummaryFiles

New bin/lib/plan-scan.cjs exports scanPhasePlans(phaseDir) → {
  planCount, summaryCount, completed, hasNestedPlans,
  planFiles, summaryFiles
}

Divergences resolved:
- roadmap.cjs used a broad isPlanFile (any .md containing PLAN in name,
  matching the extended layout 5-PLAN-01-setup.md); canonical helper
  adopts this wider pattern as the reference implementation.
- state.cjs used a strict endsWith(-PLAN.md) filter, missing extended-
  layout root files; now unified with roadmap.cjs semantics.
- init.cjs listPhasePlanFiles used ^PLAN-\d+ for nested, missing
  the -PLAN-\d+ variant state.cjs also matched; helper includes both.
- pre-bounce exclusion broadened to /.pre-bounce.md$/i (any pre-bounce
  file), not just -PLAN.*\.pre-bounce\.md (roadmap form) or flat
  .pre-bounce.md (state form).
- OUTLINE exclusion broadened to /-OUTLINE\.md$/i to catch both
  flat (-PLAN-OUTLINE.md) and nested (PLAN-01-OUTLINE.md) forms.

Sibling audit: no 5th call site found. phase.cjs:looksLikePlanFile is
a diagnostic probe for non-canonical naming (not a counter) — left
in place per its distinct purpose.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* chore(changelog): add entry for #3262 scanPhasePlans extraction

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* chore(changeset): add changeset fragment for #3262

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* docs(inventory): add plan-scan.cjs row to INVENTORY.md CLI Modules table (#3262)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(3262): update bug-3128 test + INVENTORY counts for plan-scan.cjs

- Update tests/bug-3128-roadmap-plan-count-slug-layout.test.cjs to verify
  that roadmap.cjs delegates to plan-scan.cjs (require check) and that the
  extended filter lives in plan-scan.cjs as isRootPlanFile with /PLAN/i
- Bump docs/INVENTORY.md CLI Modules headline from 46 to 47 (plan-scan.cjs)
- Regenerate docs/INVENTORY-MANIFEST.json to include cli_modules/plan-scan.cjs

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(3262): migrate two missed call sites to scanPhasePlans (k014)

- init.cjs cmdInitExecutePhase: replace inline /-PLAN\.md$/i filter
  with listPhasePlanFiles(path) to honour nested, extended-layout, OUTLINE
  and pre-bounce exclusions (CR finding)
- state.cjs cmdStateUpdateProgress: replace dual /-PLAN\.md$/i and
  /-SUMMARY\.md$/i filters with scanPhasePlans() so the progress-bar
  body field uses the same counts as buildStateFrontmatter frontmatter

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* fix(3262): correct INVENTORY-MANIFEST.json to tracked files only

Remove 3 untracked local entries from cli_modules so the manifest matches
what CI sees (47 tracked .cjs files, not 50 local). Previous regeneration
ran against the local filesystem which included cjs-command-router-adapter.cjs,
state-document.cjs, and workstream-inventory.cjs (all untracked on this branch).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

docs/INVENTORY-MANIFEST.json

@@ -283,6 +283,7 @@
       "phase-command-router.cjs",
       "phase.cjs",
       "phases-command-router.cjs",
+      "plan-scan.cjs",
       "planning-workspace.cjs",
       "profile-output.cjs",
       "profile-pipeline.cjs",

docs/INVENTORY.md

@@ -358,7 +358,7 @@ The `gsd-planner` agent is decomposed into a core agent plus reference modules t
 
 ---
 
-## CLI Modules (46 shipped)
+## CLI Modules (47 shipped)
 
 Full listing: `get-shit-done/bin/lib/*.cjs`.
 
@@ -391,6 +391,7 @@ Full listing: `get-shit-done/bin/lib/*.cjs`.
 | `phase-command-router.cjs` | Thin CJS subcommand router adapter for `gsd-tools phase` |
 | `phase.cjs` | Phase directory operations, decimal numbering, plan indexing |
 | `phases-command-router.cjs` | Thin CJS subcommand router adapter for `gsd-tools phases` |
+| `plan-scan.cjs` | Canonical phase-plan scanner — shared helper for detecting plan and summary files in flat and nested layouts (k014); consumed by `state.cjs`, `roadmap.cjs`, and `init.cjs` |
 | `planning-workspace.cjs` | Planning path/workstream seam (`planningDir`, `planningPaths`, active-workstream routing, `.planning/.lock` orchestration) |
 | `profile-output.cjs` | Profile rendering, USER-PROFILE.md and dev-preferences.md generation |
 | `profile-pipeline.cjs` | User behavioral profiling data pipeline, session file scanning |