Archive stale docs and mark historical references

docs/00-governance/CLEANUP_LOG.md

@@ -11,3 +11,12 @@
 - Updated onboarding guidance in `.kilocode/rules/project_context.md` to point new sessions to governance docs first.
 - Reclassified `PROJECT_HANDOVER.md` and `DESIGNED_VS_IMPLEMENTED_GAP_ANALYSIS.md` as historical/contextual references, not primary truth.
 - No code files modified and no file moves performed.
+- Moved `docs/PHASE2_COMPLETION_REPORT.md` to `docs/archive/phase-history/PHASE2_COMPLETION_REPORT.md`.
+- Added historical header + archival note block to:
+  - `docs/README.md`
+  - `PROJECT_HANDOVER.md`
+  - `DESIGNED_VS_IMPLEMENTED_GAP_ANALYSIS.md`
+  - `docs/INDEX.md`
+  - `docs/archive/phase-history/PHASE2_COMPLETION_REPORT.md`
+- Added a softer revision note to `README.md` instead of a historical warning.
+- Marked `docs/INDEX.md` historical in place because it currently misdirects navigation.