fix: taluka entity causing district filter to reject correct college rows

'VISNAGAR' was extracted as a taluka entity and used as district filter.
CollegeIntakeMaster stores CollegeDistrict='Mehsana' for Visnagar colleges,
so filtering by 'visnagar' rejected all M. N. COLLEGE, VISNAGAR rows.

Two-part fix:
1. query_planner: only use entity_type='district'|'city' for district filter,
not 'taluka' (talukas often appear inside college names)
2. structured_search: skip district filter entirely when college_name is
resolved — the college name is more specific and makes district redundant

query_planner.py

@@ -294,8 +294,11 @@ def build_query_plan(raw_query: str) -> QueryPlan:
     for e in processed.detected_entities:
         if e.entity_type == "college" and not college_name:
             college_name = e.matched
-        elif e.entity_type in ("district", "taluka", "city") and not district:
-            # Use matched canonical name
+        elif e.entity_type in ("district", "city") and not district:
+            # Only take actual district entities (not taluka) as district filter.
+            # Talukas often appear inside college names (e.g. "VISNAGAR" in
+            # "M. N. COLLEGE, VISNAGAR") and would cause false mismatches because
+            # CollegeDistrict stores the district ("Mehsana"), not the taluka.
             district = e.matched
 
     # ── Step 4: Additional entity extractions ────────────────────────────

structured_search.py

@@ -186,7 +186,11 @@ def _row_matches(
             return False
 
     # ── District ──────────────────────────────────────────────────────────
-    if district:
+    # Skip district filter when college_name is already resolved — the college
+    # name uniquely identifies the college and is more specific than district.
+    # (Filtering by district would incorrectly drop colleges in a taluka whose
+    #  name matches the query but whose CollegeDistrict differs from the taluka.)
+    if district and not college_name:
         dist = _district(row).lower()
         if not dist:
             return False