fix: lower autoSelectOrder to 15 for priority over built-in providers

Microsoft Edge TTS defaults to enabled=true with autoSelectOrder=30,
and always passes isConfigured (no API key needed). This caused auto-TTS
to route to Edge instead of fish-audio when both had order=30.

Lower to 15 to win priority over OpenAI (10), ElevenLabs (20), and
Microsoft (30) in the auto-selection fallback chain.

speech-provider.ts

@@ -233,7 +233,7 @@ export function buildFishAudioSpeechProvider(): SpeechProviderPlugin {
   return {
     id: "fish-audio",
     label: "Fish Audio",
-    autoSelectOrder: 30,
+    autoSelectOrder: 15,
     models: FISH_AUDIO_MODELS,
 
     resolveConfig: ({ rawConfig }) =>