fix: count actual tool calls instead of tool-related messages

tool_call_count was inaccurate in two ways:

1. Under-counting: an assistant message with N parallel tool calls
   (e.g. "kill the light and shut off the fan" = 2 ha_call_service)
   only incremented tool_call_count by 1 instead of N.

2. Over-counting: tool response messages (role=tool) also incremented
   tool_call_count, double-counting every tool interaction.

Combined: 2 parallel tool calls produced tool_call_count=3 (1 from
assistant + 2 from tool responses) instead of the correct value of 2.

Fix: only count from assistant messages with tool_calls, incrementing
by len(tool_calls) to handle parallel calls correctly. Tool response
messages no longer affect tool_call_count.

This impacts /insights and /usage accuracy for sessions with tool use.

hermes_state.py

@@ -259,12 +259,16 @@ class SessionDB:
         msg_id = cursor.lastrowid
 
         # Update counters
-        is_tool_related = role == "tool" or tool_calls is not None
-        if is_tool_related:
+        # Count actual tool calls from the tool_calls list (not from tool responses).
+        # A single assistant message can contain multiple parallel tool calls.
+        num_tool_calls = 0
+        if tool_calls is not None:
+            num_tool_calls = len(tool_calls) if isinstance(tool_calls, list) else 1
+        if num_tool_calls > 0:
             self._conn.execute(
                 """UPDATE sessions SET message_count = message_count + 1,
-                   tool_call_count = tool_call_count + 1 WHERE id = ?""",
-                (session_id,),
+                   tool_call_count = tool_call_count + ? WHERE id = ?""",
+                (num_tool_calls, session_id),
             )
         else:
             self._conn.execute(