feat(events): Add EventEmitter and instrument ai_client.py

ai_client.py

@@ -19,6 +19,7 @@ from pathlib import Path
 import file_cache
 import mcp_client
 import google.genai
+from events import EventEmitter
 
 _provider: str = "gemini"
 _model: str = "gemini-2.5-flash"
@@ -27,6 +28,9 @@ _max_tokens: int = 8192
 
 _history_trunc_limit: int = 8000
 
+# Global event emitter for API lifecycle events
+events = EventEmitter()
+
 def set_model_params(temp: float, max_tok: int, trunc_limit: int = 8000):
     global _temperature, _max_tokens, _history_trunc_limit
     _temperature = temp