feat: Roadmap K — RAG corpus management with score-based eviction (v0.13.0)

- Config: RAG_MAX_VECTORS, high/low water marks, grace period, weights
- rag.py: get_collection_count, evict_batch, maybe_evict (asyncio.Lock),
  get_rag_operational_stats, EVICTION_LOG, retrieval_count tracking
- routers/rag_admin.py: GET /api/rag/stats, POST /api/rag/flush (admin)
- Wire maybe_evict() into upload.py and ingest.py after Qdrant upsert
- 16 tests: collection stats, eviction scoring, pinned/grace/batch guards,
  endpoint auth, race lock, flush, operational stats shape
- Bump to v0.13.0

app.py

@@ -37,6 +37,7 @@ import routers.completions as completions
 import routers.upload as upload
 import routers.ingest as ingest
 import routers.hardware as hardware
+import routers.rag_admin as rag_admin
 
 # --- Logging ---
 log = logging.getLogger("jarvischat")
@@ -146,6 +147,7 @@ for router_module in [
     auth_router, conversations.router, memories.router, models.router,
     presets.router, profile.router, settings.router, skills.router,
     chat.router, search_route.router, completions.router, upload.router, ingest.router, hardware.router,
+    rag_admin.router,
 ]:
     app.include_router(router_module)