Add comprehensive ADR-007 documenting background vector database
synchronization architecture using anyio TaskGroups for in-process
concurrency. This supersedes ADR-003's conceptual background worker.
Key decisions:
- In-process architecture using anyio TaskGroups (not Celery)
- Scanner task runs hourly, detects changes via timestamp comparison
- In-memory asyncio.Queue for pending documents
- Pool of 3 concurrent processor tasks for I/O-bound embedding workloads
- Qdrant metadata as single source of truth for indexing state
- Simple user controls: enable/disable with status visibility
Benefits:
- Single container deployment (was 3: mcp, celery-worker, celery-beat)
- No distributed task queue infrastructure
- Shared process state (no volume coordination)
- Sufficient throughput for I/O-bound embedding APIs
- Simpler debugging and deployment
Update ADR-003 status to "Superseded by ADR-007" with reference link.
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Co-Authored-By: Claude <noreply@anthropic.com>
Chris Coutinho