fix(agent): hydrate memory-nudge counters from conversation_history (#22774)

Gateway creates a fresh AIAgent per inbound message in several common
scenarios: cache miss, idle eviction (1h TTL), config-signature
mismatch, process restart. A freshly-built AIAgent has
_turns_since_memory=0 and _user_turn_count=0, so the
memory.nudge_interval trigger ('_turns_since_memory >=
_memory_nudge_interval') can never be reached when these reconstructions
happen on roughly the cadence of the interval. A user can chat for hours
on Telegram without ever seeing a self-improvement review fire.

Reconstruct the counters from conversation_history at the top of
run_conversation(), right after the existing _hydrate_todo_store call.
Idempotent guard ('if self._user_turn_count == 0') means a cached agent
that already accumulated counters keeps them; only freshly-built agents
hydrate. Modulo arithmetic preserves the original 1-in-N cadence rather
than firing a review immediately on resume.

7 regression tests pinning the contract (mid-cycle history, modulo wrap,
idempotency, zero-interval skip, role==user filtering, production-code
anchor).

Closes #22357.

run_agent.py

@@ -11127,7 +11127,29 @@ class AIAgent:
         # recover the todo state from the most recent todo tool response in history)
         if conversation_history and not self._todo_store.has_items():
             self._hydrate_todo_store(conversation_history)
-        
+
+        # Hydrate per-session nudge counters from persisted history.
+        # Gateway creates a fresh AIAgent per inbound message (cache miss /
+        # 1h idle eviction / config-signature mismatch / process restart), so
+        # _turns_since_memory and _user_turn_count start at 0 every turn and
+        # the memory.nudge_interval trigger may never be reached. Reconstruct
+        # an effective count from prior user turns in conversation_history.
+        # Idempotent: a cached agent that already accumulated counters keeps
+        # them; only a freshly-built agent with empty in-memory state hydrates.
+        # See issue #22357.
+        if conversation_history and self._user_turn_count == 0:
+            prior_user_turns = sum(
+                1 for m in conversation_history if m.get("role") == "user"
+            )
+            if prior_user_turns > 0:
+                self._user_turn_count = prior_user_turns
+                if self._memory_nudge_interval > 0 and self._turns_since_memory == 0:
+                    # % preserves original 1-in-N cadence rather than firing a
+                    # review immediately on resume (which would surprise users
+                    # whose session happened to land just past a multiple of N).
+                    self._turns_since_memory = prior_user_turns % self._memory_nudge_interval
+
+
         # Prefill messages (few-shot priming) are injected at API-call time only,
         # never stored in the messages list. This keeps them ephemeral: they won't
         # be saved to session DB, session logs, or batch trajectories, but they're