feat(voice): mic button in chat widget with press-and-hold recording

- Imports onCleanup, Mic, MicOff from solid-js / lucide-solid
- [isRecording, isTranscribing] signals track state across the flow
- startRecording(): requests getUserMedia, creates MediaRecorder (prefers
  audio/webm;codecs=opus, falls back to webm then ogg), starts recording
- stopRecording(): stops MediaRecorder; onstop handler assembles Blob,
  POSTs to /api/ai/voice/transcribe as multipart 'audio' field
- transcribeAudio(): sends the Blob, populates input() with the transcript,
  then auto-sends after 600ms so the user sees it before it flies
- Mic button: grey at rest → red while recording → spinner while
  transcribing; uses onPointerDown/Up/Leave for reliable hold UX
- Red recording hint bar below input with pulsing dot while active
- onCleanup stops any in-progress MediaRecorder on widget unmount

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/AiChatWidget.tsx

@@ -1,5 +1,5 @@
-import { createSignal, Show, For, onMount } from "solid-js";
-import { MessageCircle, X, Send, Bot, User, Loader } from "lucide-solid";
+import { createSignal, Show, For, onMount, onCleanup } from "solid-js";
+import { MessageCircle, X, Send, Bot, User, Loader, Mic, MicOff } from "lucide-solid";
 
 const API = "/api";
 
@@ -110,6 +110,82 @@ export function AiChatWidget() {
   const [conversationId, setConversationId] = createSignal("");
   const [usage, setUsage] = createSignal<UsageStatus | null>(null);
 
+  // ── Voice recording state ─────────────────────────────────────────────────
+  const [isRecording, setIsRecording] = createSignal(false);
+  const [isTranscribing, setIsTranscribing] = createSignal(false);
+  let mediaRecorder: MediaRecorder | null = null;
+  let recordedChunks: BlobPart[] = [];
+
+  onCleanup(() => {
+    if (mediaRecorder && mediaRecorder.state !== "inactive") {
+      mediaRecorder.stop();
+    }
+  });
+
+  const startRecording = async () => {
+    if (isRecording() || isTranscribing()) return;
+    try {
+      const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
+      recordedChunks = [];
+      const mimeType = MediaRecorder.isTypeSupported("audio/webm;codecs=opus")
+        ? "audio/webm;codecs=opus"
+        : MediaRecorder.isTypeSupported("audio/webm")
+        ? "audio/webm"
+        : "audio/ogg";
+      mediaRecorder = new MediaRecorder(stream, { mimeType });
+      mediaRecorder.ondataavailable = (e) => {
+        if (e.data.size > 0) recordedChunks.push(e.data);
+      };
+      mediaRecorder.onstop = async () => {
+        // Stop all tracks so the mic indicator goes away
+        stream.getTracks().forEach((t) => t.stop());
+        const blob = new Blob(recordedChunks, { type: mimeType });
+        if (blob.size < 100) return; // too small — likely empty
+        await transcribeAudio(blob, mimeType);
+      };
+      mediaRecorder.start();
+      setIsRecording(true);
+    } catch {
+      // Mic permission denied or not available — fail silently
+      setIsRecording(false);
+    }
+  };
+
+  const stopRecording = () => {
+    if (!isRecording() || !mediaRecorder) return;
+    setIsRecording(false);
+    mediaRecorder.stop();
+  };
+
+  const transcribeAudio = async (blob: Blob, mimeType: string) => {
+    setIsTranscribing(true);
+    try {
+      const ext = mimeType.includes("ogg") ? "audio.ogg" : "audio.webm";
+      const formData = new FormData();
+      formData.append("audio", blob, ext);
+      const res = await fetch(`${API}/ai/voice/transcribe`, {
+        method: "POST",
+        headers: {
+          Authorization: `Bearer ${sessionStorage.getItem("nxtgauge_access_token") || ""}`,
+        },
+        credentials: "include",
+        body: formData,
+      });
+      if (!res.ok) return;
+      const data = await res.json();
+      const text: string = data.transcript || "";
+      if (text.trim()) {
+        setInput(text.trim());
+        // Auto-send after a short pause so the user can see the text first
+        setTimeout(() => sendMessage(), 600);
+      }
+    } catch {
+      // Transcription failed — leave input as-is
+    } finally {
+      setIsTranscribing(false);
+    }
+  };
+
   onMount(() => {
     const hasToken = typeof window !== "undefined" && !!sessionStorage.getItem("nxtgauge_access_token");
     if (hasToken) fetchUsage();
@@ -696,6 +772,41 @@ export function AiChatWidget() {
                 outline: "none",
               }}
             />
+            {/* Mic button — hold to record, release to transcribe */}
+            <button
+              onPointerDown={startRecording}
+              onPointerUp={stopRecording}
+              onPointerLeave={stopRecording}
+              disabled={isLoading() || isTranscribing()}
+              aria-label={isRecording() ? "Stop recording" : "Hold to record voice message"}
+              title={isRecording() ? "Release to send" : "Hold to record"}
+              style={{
+                width: "40px",
+                height: "40px",
+                "border-radius": "50%",
+                background: isRecording()
+                  ? "#EF4444"
+                  : isTranscribing()
+                  ? "#E5E7EB"
+                  : "#F3F4F6",
+                border: isRecording() ? "2px solid #FCA5A5" : "1px solid #E5E7EB",
+                cursor: isLoading() || isTranscribing() ? "default" : "pointer",
+                display: "flex",
+                "align-items": "center",
+                "justify-content": "center",
+                transition: "background 0.15s, border 0.15s",
+                "flex-shrink": "0",
+              }}
+            >
+              <Show when={isTranscribing()} fallback={
+                <Show when={isRecording()} fallback={<Mic size={16} color="#6B7280" />}>
+                  <MicOff size={16} color="#fff" />
+                </Show>
+              }>
+                <Loader size={14} color="#9CA3AF" style={{ animation: "spin 1s linear infinite" }} />
+              </Show>
+            </button>
+
             <button
               onClick={sendMessage}
               disabled={isLoading() || !input().trim()}
@@ -710,11 +821,30 @@ export function AiChatWidget() {
                 display: "flex",
                 "align-items": "center",
                 "justify-content": "center",
+                "flex-shrink": "0",
               }}
             >
               <Send size={16} color="#fff" />
             </button>
           </div>
+
+          {/* Recording hint bar */}
+          <Show when={isRecording()}>
+            <div style={{
+              padding: "6px 16px",
+              background: "#FEF2F2",
+              "border-top": "1px solid #FECACA",
+              display: "flex",
+              "align-items": "center",
+              gap: "8px",
+              "font-size": "11px",
+              color: "#EF4444",
+              "font-weight": "600",
+            }}>
+              <span style={{ width: "8px", height: "8px", "border-radius": "50%", background: "#EF4444", display: "inline-block", animation: "pulse 1s ease-in-out infinite" }} />
+              Recording… release to transcribe
+            </div>
+          </Show>
         </div>
       </Show>
 
@@ -723,6 +853,10 @@ export function AiChatWidget() {
           from { transform: rotate(0deg); }
           to { transform: rotate(360deg); }
         }
+        @keyframes pulse {
+          0%, 100% { opacity: 1; }
+          50% { opacity: 0.3; }
+        }
       `}</style>
     </>
   );