fix: define project context ownership and freshness

[rainypilgrimage]

Summary

• separate stable memory, one canonical current-status source, source materials, and route-only indexes under the One fact, one owner rule
• add a bilingual Freshness Gate and narrow update memory to reviewed stable memory instead of project-wide synchronization
• document the boundary in both READMEs and add runtime-generated fictional Project Alpha regression scenarios
• strengthen bilingual semantic parity and privacy checks without adding services, databases, background scanning, or mandatory migration

Validation

• npm test — 9 tests passed, 0 failed
• skill structure validation — passed
• tracked-content privacy scan — no matches
• fresh-agent scenarios — newer authoritative source selected; duplicate current-status owners require user choice before writes

Version boundary

This is a v0.8.1 reliability patch. It does not add sync project context, background polling, automatic migration, or bulk migration.