feat: ingest source-aware messaging bundles

[0thernet]

Summary

• ingest strict Wrench Message Like Me v1 bundles and inspect redacted per-source health
• migrate the local store to source-aware v3 semantics with stable namespaces, bounded snapshot replacement, explicit suppression, and undated reaction facts
• preserve iMessage profiles and evidence while adding mixed-service metrics, the exact Wrench golden fixture, and a v0.3.0 site
• document the direct official Beeper CLI path, sequential per-account progress, atomic publication, and why the MCP is outside this export boundary

Verification

• bun run check: 80 tests, 633 assertions, typecheck, skill/privacy checks, fresh distribution, and packed-consumer smoke
• site: 6 tests, ESLint, generated README parity, and Vinext production build
• exact bundle fixture remains byte-identical to Wrench's checked producer fixture
• local live import and doctor validation completed across nine connected accounts without storing credentials in Message Like Me

Requires the Wrench v0.13.0 producer release from hraness/wrench#38.