feat(chat): add per-message read-aloud TTS playback (#1305)

app/src/main/java/com/m57/hermescontrol/data/model/Tts.kt

@@ -0,0 +1,26 @@
+package com.m57.hermescontrol.data.model
+
+import kotlinx.serialization.Serializable
+
+/**
+ * Request body for `POST /api/audio/speak` — the dashboard's server-side
+ * text-to-speech relay.
+ */
+@Serializable
+data class TtsSpeakRequest(
+    val text: String,
+)
+
+/**
+ * Response of `POST /api/audio/speak`.
+ *
+ * Returns base64 encoded [data_url] with [mime_type] and the [provider] used,
+ * or [ok] = false on failure.
+ */
+@Serializable
+data class TtsSpeakResponse(
+    val ok: Boolean = false,
+    val data_url: String? = null,
+    val mime_type: String? = null,
+    val provider: String? = null,
+)

app/src/main/java/com/m57/hermescontrol/data/remote/HermesApiService.kt

@@ -134,6 +134,8 @@ import com.m57.hermescontrol.data.model.ToolsetPostSetupResponse
 import com.m57.hermescontrol.data.model.ToolsetProviderSelectRequest
 import com.m57.hermescontrol.data.model.ToolsetProviderSelectResponse
 import com.m57.hermescontrol.data.model.ToolsetToggleRequest
+import com.m57.hermescontrol.data.model.TtsSpeakRequest
+import com.m57.hermescontrol.data.model.TtsSpeakResponse
 import com.m57.hermescontrol.data.model.UpdateCheckResponse
 import com.m57.hermescontrol.data.model.UpdateCronJobRequest
 import com.m57.hermescontrol.data.model.UpdateProfileDescriptionRequest
@@ -1043,4 +1045,10 @@ interface HermesApiService : KanbanApiService {
     suspend fun transcribeAudio(
         @Body body: AudioTranscriptionRequest,
     ): Response<AudioTranscriptionResponse>
+
+    @POST("api/audio/speak")
+    suspend fun speakText(
+        @Body request: TtsSpeakRequest,
+        @Query("profile") profile: String? = null,
+    ): Response<TtsSpeakResponse>
 }