fix(tasks): replace fire-and-forget asyncio.create_task with create_tracked_task

Add utils/task_tracker.py with create_tracked_task() that wraps background
tasks with error logging, cancellation handling, and reference tracking.

Replace all 17 fire-and-forget asyncio.create_task() calls across 7 files:
- bot/bot.py (5 interjection checks)
- bot/utils/autonomous.py (2 check-and-act/react tasks)
- bot/utils/bipolar_mode.py (3 argument tasks)
- bot/commands/uno.py (1 game loop task)
- bot/utils/voice_receiver.py (3 STT/interruption callbacks)
- bot/utils/persona_dialogue.py (4 dialogue turn/interjection tasks)

Previously-tracked tasks (voice_audio.py, voice_manager.py) were left as-is
since they already store task references for cancellation.

Closes #1

bot/utils/voice_receiver.py

@@ -17,6 +17,7 @@ import discord
 from discord.ext import voice_recv
 
 from utils.stt_client import STTClient
+from utils.task_tracker import create_tracked_task
 
 logger = logging.getLogger('voice_receiver')
 
@@ -256,11 +257,11 @@ class VoiceReceiverSink(voice_recv.AudioSink):
         stt_client = STTClient(
             user_id=user_id,
             stt_url=self.stt_url,
-            on_partial_transcript=lambda text, timestamp: asyncio.create_task(
-                self._on_partial_transcript(user_id, text)
+            on_partial_transcript=lambda text, timestamp: create_tracked_task(
+                self._on_partial_transcript(user_id, text), task_name="stt_partial_transcript"
             ),
-            on_final_transcript=lambda text, timestamp: asyncio.create_task(
-                self._on_final_transcript(user_id, text, user)
+            on_final_transcript=lambda text, timestamp: create_tracked_task(
+                self._on_final_transcript(user_id, text, user), task_name="stt_final_transcript"
             ),
         )
         
@@ -421,8 +422,9 @@ class VoiceReceiverSink(voice_recv.AudioSink):
                             self.interruption_audio_count.pop(user_id, None)
                             
                             # Call interruption handler (this sets miku_speaking=False)
-                            asyncio.create_task(
-                                self.voice_manager.on_user_interruption(user_id)
+                            create_tracked_task(
+                                self.voice_manager.on_user_interruption(user_id),
+                                task_name="voice_user_interruption"
                             )
                     else:
                         # Audio below RMS threshold (silence) - reset interruption tracking