Strip Jarvis/Sage personas, simplify to MoltMic pipe

- Replace /jarvis and /sage command groups with /moltmic join|leave|status
- Remove AgentVoiceConfig, AgentsConfig now just has default agent
- Remove voice file checks from run.py (cloud TTS doesn't need them)
- Remove agent-to-voice mapping in bot.py on_speech_complete
- Rename from 'Jarvis Voice Bot' to 'MoltMic' throughout

config.yaml

@@ -22,32 +22,7 @@ discord:
 # Agent Configuration
 # ============================================================================
 agents:
-  # Default agent (jarvis or sage)
-  default: "jarvis"
-
-  # Per-agent settings
-  jarvis:
-    # TTS voice reference file (relative to server/voices/)
-    voice_file: "jarvis.mp3"
-
-    # Agent personality for LLM context
-    personality: |
-      You are Jarvis, an intelligent, witty, and helpful AI assistant.
-      You speak naturally and conversationally, with subtle British sophistication.
-      You provide accurate information and thoughtful insights without being
-      verbose. You have a dry sense of humor but know when to be serious.
-
-    # TTS emotion exaggeration (0.0 = none, 1.0 = full)
-    emotion_exaggeration: 0.3
-
-  sage:
-    voice_file: "sage.wav"
-    personality: |
-      You are Sage, a wise, calm, and philosophical AI assistant.
-      You speak thoughtfully and deliberately, offering deep insights and
-      perspectives. You are patient, empathetic, and help people think through
-      complex problems. Your tone is warm and encouraging.
-    emotion_exaggeration: 0.2
+  default: "main"
 
 # ============================================================================
 # OpenClaw Gateway