feat(#1430): versioned capability manifest + native stamping (ADR-1244 Phase 1) (#1436)

* feat(#1430): versioned capability manifest + native stamping (ADR-1244 Phase 1)

Make the capability manifest versioned — the data substrate the Capability
Ecosystem (ADR-1244) keys off:

- capability.json gains a REQUIRED semver `version` plus the optional
  ecosystem envelope (`engines.gsd`, `compatVersions`, `integrity`,
  `provenance`); the build-time conformance validator enforces them via a new
  `validateVersionEnvelope()` (exported for the Phase 2 runtime overlay).
- All 32 native capabilities stamped with `version` (= package version,
  lockstep) + `engines.gsd`; `sync-manifest-versions.cjs` gains a glob sweep
  that keeps them in sync, and the issue-844 regression guard is extended.
- Strict SemVer 2.0.0 grammar blocks metacharacter/space/unicode smuggling in
  version strings; range/integrity fields are shape-validated (satisfaction
  and the load-time gate are deferred to Phase 2/4).
- Capability rel-paths emitted forward-slash for cross-platform git correctness.

Closes #1430

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

* docs(#1430): add changeset for versioned capability manifest

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

---------

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

capabilities/gap-analysis/capability.json

@@ -1,11 +1,20 @@
 {
   "id": "gap-analysis",
   "role": "feature",
+  "version": "1.5.1-dev.0",
   "title": "Post-planning gap analysis",
   "description": "Proactive, non-blocking post-planning coverage report. After all PLAN.md files are generated, cross-references every REQ-ID and D-ID from REQUIREMENTS.md and CONTEXT.md against plan bodies. Emits a Source | Item | Status table. Does not block phase advancement.",
   "tier": "standard",
   "requires": [],
-  "runtimeCompat": { "supported": ["*"], "unsupported": [] },
+  "engines": {
+    "gsd": ">=1.6.0"
+  },
+  "runtimeCompat": {
+    "supported": [
+      "*"
+    ],
+    "unsupported": []
+  },
   "skills": [],
   "agents": [],
   "hooks": [],