feat(agent): add voice input and photo attachments to assistant

Wire mic through Whisper-compatible transcriptions on LLM_BASE_URL.

Photos upload to MinIO and reach the vision model as base64 image_url parts.

src/modules/agent/components/use-voice-input.ts

@@ -0,0 +1,129 @@
+"use client";
+
+import { useCallback, useEffect, useRef, useState } from "react";
+
+export type VoiceInputState = "idle" | "recording" | "transcribing";
+
+function pickRecorderFormat(): { mimeType: string; extension: string } {
+  const candidates = [
+    { mimeType: "audio/wav", extension: "wav" },
+    { mimeType: "audio/webm;codecs=opus", extension: "webm" },
+    { mimeType: "audio/webm", extension: "webm" },
+    { mimeType: "audio/mp4", extension: "m4a" },
+  ];
+
+  for (const candidate of candidates) {
+    if (typeof MediaRecorder !== "undefined" && MediaRecorder.isTypeSupported(candidate.mimeType)) {
+      return candidate;
+    }
+  }
+
+  return { mimeType: "", extension: "webm" };
+}
+
+export function useVoiceInput(options: {
+  onTranscript: (text: string) => void;
+  onError: (message: string) => void;
+  disabled?: boolean;
+}) {
+  const [state, setState] = useState<VoiceInputState>("idle");
+  const recorderRef = useRef<MediaRecorder | null>(null);
+  const chunksRef = useRef<Blob[]>([]);
+  const streamRef = useRef<MediaStream | null>(null);
+  const formatRef = useRef(pickRecorderFormat());
+  const onTranscriptRef = useRef(options.onTranscript);
+  const onErrorRef = useRef(options.onError);
+
+  useEffect(() => {
+    onTranscriptRef.current = options.onTranscript;
+    onErrorRef.current = options.onError;
+  }, [options.onTranscript, options.onError]);
+
+  const stopStream = useCallback(() => {
+    for (const track of streamRef.current?.getTracks() ?? []) {
+      track.stop();
+    }
+    streamRef.current = null;
+  }, []);
+
+  const stopRecording = useCallback(async () => {
+    const recorder = recorderRef.current;
+    if (!recorder || recorder.state === "inactive") return;
+
+    await new Promise<void>((resolve) => {
+      recorder.addEventListener("stop", () => resolve(), { once: true });
+      recorder.stop();
+    });
+
+    recorderRef.current = null;
+    stopStream();
+
+    const blob = new Blob(chunksRef.current, {
+      type: formatRef.current.mimeType || chunksRef.current[0]?.type || "audio/webm",
+    });
+    chunksRef.current = [];
+
+    if (blob.size === 0) {
+      setState("idle");
+      onErrorRef.current("No audio captured");
+      return;
+    }
+
+    setState("transcribing");
+    try {
+      const formData = new FormData();
+      formData.append("file", blob, `recording.${formatRef.current.extension}`);
+      const response = await fetch("/api/agent/transcribe", { method: "POST", body: formData });
+      if (!response.ok) {
+        const payload = (await response.json().catch(() => null)) as { error?: string } | null;
+        throw new Error(payload?.error ?? "Transcription failed");
+      }
+      const payload = (await response.json()) as { text: string };
+      onTranscriptRef.current(payload.text);
+    } catch (err) {
+      onErrorRef.current(err instanceof Error ? err.message : "Transcription failed");
+    } finally {
+      setState("idle");
+    }
+  }, [stopStream]);
+
+  const startRecording = useCallback(async () => {
+    if (options.disabled || state !== "idle") return;
+    if (typeof navigator === "undefined" || !navigator.mediaDevices?.getUserMedia) {
+      onErrorRef.current("Microphone not available in this browser");
+      return;
+    }
+
+    formatRef.current = pickRecorderFormat();
+
+    try {
+      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
+      streamRef.current = stream;
+      const recorder = formatRef.current.mimeType
+        ? new MediaRecorder(stream, { mimeType: formatRef.current.mimeType })
+        : new MediaRecorder(stream);
+      chunksRef.current = [];
+      recorder.addEventListener("dataavailable", (event) => {
+        if (event.data.size > 0) chunksRef.current.push(event.data);
+      });
+      recorder.start();
+      recorderRef.current = recorder;
+      setState("recording");
+    } catch {
+      stopStream();
+      onErrorRef.current("Microphone permission denied");
+    }
+  }, [options.disabled, state, stopStream]);
+
+  const toggleRecording = useCallback(async () => {
+    if (state === "recording") {
+      await stopRecording();
+      return;
+    }
+    if (state === "idle") {
+      await startRecording();
+    }
+  }, [startRecording, state, stopRecording]);
+
+  return { state, toggleRecording };
+}