Remove corpus counts from chat chrome

apps/ai-service/rag/service.py

@@ -270,6 +270,13 @@ class RetrievalService:
     # Excluded from pooling outright rather than trusting a score margin
     # that isn't reliably wide enough on its own.
     _LEXICAL_POOL_EXCLUDED_SECTIONS = frozenset({"duoc_ly_va_co_che_tac_dung"})
+    # Cross-section pooling solves one measured semantic mismatch: a
+    # "thận trọng" question whose decisive condition is filed under
+    # contraindications. Applying it to every explicit section leaked a
+    # lexically-overlapping interaction section into a dosage answer. Keep
+    # this recall expansion opt-in for the one section with evidence for it;
+    # exact dosage/interaction/contraindication routes remain exact.
+    _LEXICAL_POOL_ENABLED_SECTIONS = frozenset({"than_trong"})
 
     def _section_hits(self, query: str, drug_id: str) -> list[SearchHit] | None:
         """Hits for an explicitly named section, or None to fall back.
@@ -302,6 +309,8 @@ class RetrievalService:
         as into a query-driven check across every section, still bounded and
         still whole-section (never a partial, out-of-context fragment).
         """
+        if resolved_section not in self._LEXICAL_POOL_ENABLED_SECTIONS:
+            return []
         search_lexical = getattr(self._retriever, "search_lexical", None)
         if search_lexical is None:
             return []