feat: add Edge TTS rate/pitch sliders to voice settings (#629)

Add speed (rate) and pitch controls for Edge TTS provider:
- Frontend: speedToEdgeRate()/hzToEdgePitch() helpers + UI sliders
- Backend: rate/pitch passthrough in OpenaiTtsRequest and controller
- i18n: add edgeRate/edgePitch keys across all 8 languages
- Rate: 0.5x-2.0x slider, Pitch: -20Hz to +20Hz slider

packages/server/src/controllers/hermes/tts.ts

@@ -38,6 +38,8 @@ export async function openaiProxy(ctx: Context) {
     voice?: string
     speed?: number
     model?: string
+    rate?: string
+    pitch?: string
   }
 
   if (!body.input || typeof body.input !== 'string') {
@@ -57,6 +59,8 @@ export async function openaiProxy(ctx: Context) {
     voice: body.voice,
     speed: body.speed,
     model: body.model,
+    rate: body.rate,
+    pitch: body.pitch,
   })
 
   ctx.set('Content-Type', 'audio/mpeg')

packages/server/src/services/hermes/tts.ts

@@ -64,6 +64,8 @@ export interface OpenaiTtsRequest {
   input: string
   voice?: string
   speed?: number
+  rate?: string   // Edge TTS rate format, e.g. "+20%". Takes priority over speed.
+  pitch?: string  // Edge TTS pitch format, e.g. "-8Hz"
 }
 
 export async function openaiCompatibleTts(
@@ -72,7 +74,7 @@ export async function openaiCompatibleTts(
   return textToSpeech({
     text: body.input,
     voice: body.voice || FIXED_VOICE,
-    rate: body.speed ? speedToEdgeRate(body.speed) : FIXED_RATE,
-    pitch: FIXED_PITCH,
+    rate: body.rate || (body.speed ? speedToEdgeRate(body.speed) : FIXED_RATE),
+    pitch: body.pitch || FIXED_PITCH,
   })
 }