feat: add /memory/pin and /memory/importance endpoints

[ajianaz]

Summary

No API endpoints for pinning or setting importance. These exist in CLI but not HTTP server.

Proposed

POST /memory/pin    {"id": "uuid", "pinned": true/false}
POST /memory/importance {"id": "uuid", "importance": 0.9}

Acceptance Criteria

Functional

• POST /memory/pin — pin or unpin a memory
• POST /memory/importance — set importance (0.0-1.0)
• Validation: importance must be 0.0-1.0

Verification (CMO can run without reading code)

• curl POST /memory/pin {"id":"<existing>","pinned":true} → 200, memory now pinned
• curl POST /memory/pin {"id":"<existing>","pinned":false} → 200, memory unpinned
• curl POST /memory/pin {"id":"<existing>"} (omit pinned) → 200, defaults to pin (toggle on)
• curl POST /memory/importance {"id":"<existing>","importance":0.85} → 200, importance = 0.85
• curl POST /memory/importance {"id":"<existing>","importance":1.5} → 400 validation error
• curl POST /memory/importance {"id":"<existing>","importance":-0.1} → 400 validation error
• curl POST /memory/pin {"id":"nonexistent"} → 404
• Both endpoints return the full updated memory object

Tests

• Unit: pin → verify pinned column = 1
• Unit: importance → verify column = exact value
• Unit: importance out of range → 400

Priority

Low — could be superseded by PUT /memory (#658).

Dependencies

Could be superseded by #658 (PUT /memory).

[ajianaz]

Related

• feat: add PUT /memory endpoint for updating existing memories #659 (PUT /memory) would make these dedicated endpoints optional