feat: implement matching router with two-stage retrieval, reranking, and async explanation generation

backend/src/routers/matching.py

@@ -74,8 +74,8 @@ async def trigger_match(
     jd_id: uuid.UUID,
     request: Request,
     session_id: uuid.UUID | None = Query(None, description="Candidate session to match against"),
-    stage1_top_k: int = Query(100, ge=10, le=500, description="How many candidates to retrieve from vector DB (Stage 1)"),
-    stage2_top_k: int = Query(40, ge=5, le=250, description="How many Stage 1 candidates to pass to the neural reranker (Stage 2)"),
+    stage1_top_k: int = Query(100, description="How many candidates to retrieve from vector DB (Stage 1)"),
+    stage2_top_k: int = Query(100, description="How many Stage 1 candidates to pass to the neural reranker (Stage 2)"),
     db: AsyncSession = Depends(get_db),
 ):
     jd = await _load_jd(jd_id, db)