Update chat events/transcription flow and container startup fixes

Frontend/server/utils/whisper.ts

@@ -0,0 +1,53 @@
+type WhisperTranscribeInput = {
+  samples: Float32Array;
+  sampleRate: number;
+  language?: string;
+};
+let whisperPipelinePromise: Promise<any> | null = null;
+let transformersPromise: Promise<any> | null = null;
+
+function getWhisperModelId() {
+  return (process.env.CF_WHISPER_MODEL ?? "Xenova/whisper-small").trim() || "Xenova/whisper-small";
+}
+
+function getWhisperLanguage() {
+  const value = (process.env.CF_WHISPER_LANGUAGE ?? "ru").trim();
+  return value || "ru";
+}
+
+async function getWhisperPipeline() {
+  if (!transformersPromise) {
+    transformersPromise = import("@xenova/transformers");
+  }
+
+  const { env, pipeline } = await transformersPromise;
+
+  if (!whisperPipelinePromise) {
+    env.allowRemoteModels = true;
+    env.allowLocalModels = true;
+    env.cacheDir = "/app/.data/transformers";
+
+    const modelId = getWhisperModelId();
+    whisperPipelinePromise = pipeline("automatic-speech-recognition", modelId);
+  }
+
+  return whisperPipelinePromise;
+}
+
+export async function transcribeWithWhisper(input: WhisperTranscribeInput) {
+  const transcriber = (await getWhisperPipeline()) as any;
+  const result = await transcriber(
+    input.samples,
+    {
+      sampling_rate: input.sampleRate,
+      language: (input.language ?? getWhisperLanguage()) || "ru",
+      task: "transcribe",
+      chunk_length_s: 20,
+      stride_length_s: 5,
+      return_timestamps: false,
+    },
+  );
+
+  const text = String((result as any)?.text ?? "").trim();
+  return text;
+}