feat: Phase 1 ingestion hardening + Phase 5 Trusted Project State

Phase 1 - Ingestion hardening:
- Encoding fallback (UTF-8/UTF-8-sig/Latin-1/CP1252)
- Delete detection: purge DB/vector entries for removed files
- Ingestion stats endpoint (GET /stats)

Phase 5 - Trusted Project State:
- project_state table with categories (status, decision, requirement, contact, milestone, fact, config)
- CRUD API: POST/GET/DELETE /project/state
- Upsert semantics, invalidation (supersede) support
- Context builder integrates project state at highest trust precedence
- Project state gets 20% budget allocation, appears first in context
- Trust precedence: Project State > Retrieved Chunks (per Master Plan)

33/33 tests passing. Validated end-to-end with GigaBIT M1 project data.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/atocore/main.py

@@ -4,6 +4,7 @@ from fastapi import FastAPI
 
 from atocore.api.routes import router
 from atocore.config import settings
+from atocore.context.project_state import init_project_state_schema
 from atocore.models.database import init_db
 from atocore.observability.logger import setup_logging
 
@@ -20,6 +21,7 @@ app.include_router(router)
 def startup():
     setup_logging()
     init_db()
+    init_project_state_schema()
 
 
 if __name__ == "__main__":