Fix webhook avatar mismatch: pass avatar_url at send time

- Fixed missing client parameter in animated GIF webhook update path
- Added get_persona_avatar_urls() helper that returns bot's current Discord
  avatar URL for Miku persona (always fresh, no cache lag)
- Pass avatar_url on every webhook.send() call in bipolar_mode.py,
  persona_dialogue.py, and api.py so avatars always match current pfp
  regardless of webhook cache state

bot/utils/profile_picture_manager.py

@@ -442,10 +442,13 @@ class ProfilePictureManager:
                         
                         # Update bipolar webhook avatars if bipolar mode is active
                         if globals.BIPOLAR_MODE:
-                            from bot.utils.bipolar_mode import update_webhook_avatars
-                            updated = await update_webhook_avatars()
-                            if debug:
-                                logger.info(f"Updated bipolar webhook avatars: {updated}")
+                            try:
+                                from utils.bipolar_mode import update_webhook_avatars
+                                updated = await update_webhook_avatars(globals.client)
+                                if debug:
+                                    logger.info(f"Updated bipolar webhook avatars: {updated}")
+                            except Exception as e:
+                                logger.warning(f"Failed to update bipolar webhook avatars: {e}")
                         
                         return result