chore(memory): fix shared-memory index issues

Audit of .claude/memory found and fixed:
- Broken link: Power Failure Runbook (../.claude/... -> ../...)
- 8 orphaned memories not in MEMORY.md index (Graph CA/password-reset,
  vault-write-sequence, GURU-BEAST-ROG, 3x Cascades, identity proposal)
  -> now indexed under their sections, so they're discoverable
- 5 files missing frontmatter -> added name/description/type
- Duplicate index entry for reference_workstation_setup.md -> deduped
- Trimmed the worst oversized index hooks (Syncro invoice line was 427 chars)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.claude/memory/proposal_identity_centralization.md

@@ -1,3 +1,9 @@
+---
+name: Proposal — centralize machine config in identity.json
+description: Rationale for moving per-machine config (ollama endpoint/model, python cmd, platform, claudetools_root) into identity.json instead of per-script detection. Implemented 2026-05-27.
+type: project
+---
+
 # Proposal: Centralize Machine-Specific Config in identity.json
 
 ## Problem