fix(gateway): re-inject topic-bound skill after /new or /reset

reset_session() creates a fresh SessionEntry with created_at == updated_at,
but get_or_create_session() bumps updated_at on the next inbound message,
causing _is_new_session in _handle_message_with_agent to evaluate False.
The topic/channel skill auto-load gate (group_topics, channel_skill_bindings)
silently skips the first message after a manual reset.

Add an is_fresh_reset flag on SessionEntry, set by reset_session() and
consumed once by the message handler. Kept distinct from was_auto_reset
because that flag also drives a 'session expired due to inactivity'
user-facing notice and a context-note prepend — both wrong for an
explicit /new or /reset.

Persisted through to_dict/from_dict so the flag survives gateway
restart between /reset and the next message.

Fixes #6508

Co-authored-by: warabe1122 <45554392+warabe1122@users.noreply.github.com>
Co-authored-by: willy-scr <187001140+willy-scr@users.noreply.github.com>

gateway/run.py

@@ -5300,7 +5300,12 @@ class GatewayRunner:
         _is_new_session = (
             session_entry.created_at == session_entry.updated_at
             or getattr(session_entry, "was_auto_reset", False)
+            or getattr(session_entry, "is_fresh_reset", False)
         )
+        # Consume the is_fresh_reset flag immediately so it doesn't leak
+        # onto subsequent messages in the same session (issue #6508).
+        if getattr(session_entry, "is_fresh_reset", False):
+            session_entry.is_fresh_reset = False
         if _is_new_session:
             await self.hooks.emit("session:start", {
                 "platform": source.platform.value if source.platform else "",

gateway/session.py

@@ -458,6 +458,15 @@ class SessionEntry:
     was_auto_reset: bool = False
     auto_reset_reason: Optional[str] = None  # "idle" or "daily"
     reset_had_activity: bool = False  # whether the expired session had any messages
+
+    # Set by reset_session() when the user explicitly sends /new or /reset.
+    # Consumed once by _handle_message_with_agent to trigger topic/channel
+    # skill re-injection on the first message of the new session.  We can't
+    # reuse was_auto_reset for this because that flag fires the "session
+    # expired due to inactivity" user-facing notice and a misleading
+    # context-note prepend — both wrong for an explicit manual reset.
+    # See issue #6508.
+    is_fresh_reset: bool = False
     
     # Set by the background expiry watcher after it finalizes an expired
     # session (invoking on_session_finalize hooks and evicting the cached
@@ -508,6 +517,7 @@ class SessionEntry:
                 if self.last_resume_marked_at
                 else None
             ),
+            "is_fresh_reset": self.is_fresh_reset,
         }
         if self.origin:
             result["origin"] = self.origin.to_dict()
@@ -556,6 +566,7 @@ class SessionEntry:
             resume_pending=data.get("resume_pending", False),
             resume_reason=data.get("resume_reason"),
             last_resume_marked_at=last_resume_marked_at,
+            is_fresh_reset=data.get("is_fresh_reset", False),
         )
 
 
@@ -1132,6 +1143,7 @@ class SessionStore:
                 display_name=old_entry.display_name,
                 platform=old_entry.platform,
                 chat_type=old_entry.chat_type,
+                is_fresh_reset=True,
             )
 
             self._entries[session_key] = new_entry