feat: UAC USB microphone passthrough

- Add UAC1 gadget function (ConfigFS) with optimized endpoint config
- Browser mic capture with Opus encoding via WebCodecs AudioEncoder
- WebSocket audio transport (Opus 64kbps, 100x bandwidth reduction vs raw PCM)
- aplay subprocess for reliable PCM playback to USB gadget
- Settings toggle + ActionBar mic button (hidden when UAC disabled)
- Dynamic PCM device resolution (/proc/asound)
- c_chmask=0 + req_number=4 fixes DWC3 composite isochronous endpoint issue

web/package-lock.json

@@ -13,6 +13,7 @@
         "clsx": "^2.1.1",
         "lucide-vue-next": "^0.556.0",
         "opus-decoder": "^0.7.11",
+        "opus-media-recorder": "^0.8.0",
         "pinia": "^3.0.4",
         "qrcode.vue": "^3.10.0",
         "reka-ui": "^2.10.1",
@@ -1940,6 +1941,12 @@
       "integrity": "sha512-7z22QmUWiQ/2d0KkdYmANbRUVABpZ9SNYyH5vx6PZ+nE5bcC0l7uFvEfHlyld/HcGBFTL536ClDt3DEcSlEJAQ==",
       "license": "MIT"
     },
+    "node_modules/detect-browser": {
+      "version": "4.8.0",
+      "resolved": "https://registry.npmmirror.com/detect-browser/-/detect-browser-4.8.0.tgz",
+      "integrity": "sha512-f4h2dFgzHUIpjpBLjhnDIteXv8VQiUm8XzAuzQtYUqECX/eKh67ykuiVoyb7Db7a0PUSmJa3OGXStG0CbQFUVw==",
+      "license": "MIT"
+    },
     "node_modules/detect-libc": {
       "version": "2.1.2",
       "resolved": "https://registry.npmmirror.com/detect-libc/-/detect-libc-2.1.2.tgz",
@@ -2041,6 +2048,15 @@
       "integrity": "sha512-Rfkk/Mp/DL7JVje3u18FxFujQlTNR2q6QfMSMB7AvCBx91NGj/ba3kCfza0f6dVDbw7YlRf/nDrn7pQrCCyQ/w==",
       "license": "MIT"
     },
+    "node_modules/event-target-shim": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmmirror.com/event-target-shim/-/event-target-shim-3.0.2.tgz",
+      "integrity": "sha512-HK5GhnEAkm7fLy249GtF7DIuYmjLm85Ft6ssj7DhVl8Tx/z9+v0W6aiIVUdT4AXWGYy5Fc+s6gqBI49Bf0LejQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
     "node_modules/fdir": {
       "version": "6.5.0",
       "resolved": "https://registry.npmmirror.com/fdir/-/fdir-6.5.0.tgz",
@@ -2472,6 +2488,16 @@
         "url": "https://github.com/sponsors/eshaz"
       }
     },
+    "node_modules/opus-media-recorder": {
+      "version": "0.8.0",
+      "resolved": "https://registry.npmmirror.com/opus-media-recorder/-/opus-media-recorder-0.8.0.tgz",
+      "integrity": "sha512-AIvJMpnJqZ18dFAU7Amtt5cZZp8oPzDoAOtobdTcLzwVNm/j815+GJmBupBzBZGBa4L940TEulm7Uu4tGOYDGQ==",
+      "license": "MIT",
+      "dependencies": {
+        "detect-browser": "^4.1.0",
+        "event-target-shim": "^3.0.2"
+      }
+    },
     "node_modules/path-browserify": {
       "version": "1.0.1",
       "resolved": "https://registry.npmmirror.com/path-browserify/-/path-browserify-1.0.1.tgz",