feat: coordinate project context updates

[rainypilgrimage]

Summary

• Treat update memory, update project context, and wrap-up requests as one coordinated project-context update.
• Keep the four ownership roles internal so users do not need to choose a storage layer.
• Filter transient, duplicate, unsupported, rejected, obsolete, and no-op candidates.
• Present one consolidated preview and request one confirmation; request no confirmation when nothing needs updating.
• Preserve v0.8.1 one-fact/one-owner, route-only index, Freshness Gate, lifecycle, and explicit-confirmation safeguards.

Boundaries

• No background synchronization, workspace-wide scanning, live polling, bulk migration, destructive lifecycle action, or unconfirmed write.
• No real personal memory or private project data is included in tests.

Validation

• npm test: 9/9 passing
• quick_validate.py: skill valid
• git diff --check: passing
• Privacy scan: 0 personal-identifier matches
• Fresh-agent forward tests: coordinated wrap-up and zero-change scenarios both passed using temporary fictional Project Alpha data