Remove chat rate limit

apps/ai-service/rag/agent.py

@@ -335,7 +335,20 @@ class RagAgent:
                     ),
                     turn_type=tt,
                 )
-            if frame.condition_relation != ConditionRelation.INDICATION:
+            # UNKNOWN is treated as INDICATION here, not as a third rejection
+            # state: turn_type is already condition_to_drug/symptom_to_drug at
+            # this point, which only exists because the turn was read as
+            # asking which drug treats the condition -- that already settles
+            # the direction. Only an explicit reverse-relation reading
+            # (ADVERSE_EFFECT/CONTRAINDICATION) should abstain here; UNKNOWN
+            # is the model hedging on an ordinary question, not a genuine
+            # reverse-relation query (found live 2026-08-13: bare "X thì dùng
+            # thuốc gì" turns were reliably classified with the right
+            # turn_type but condition_relation="unknown", incorrectly
+            # aborting a plain treatment-lookup question).
+            if frame.condition_relation in (
+                ConditionRelation.ADVERSE_EFFECT, ConditionRelation.CONTRAINDICATION,
+            ):
                 return AgentReply(
                     "abstain",
                     "unsupported_reverse_relation",