Voice replies, on-device speech, message cards and 0.1.0-alpha

Gearslip now reads messages aloud and takes replies by voice. It asks
whether to reply, reads the reply back and sends it after a countdown.
Say "cancel" or "change it" to stop or redo it, or tap a quick reply.

Speech-to-text runs on the phone with whisper.cpp and a small Whisper
model, so voice works without Google services. The model ships in the
repo, so a fresh clone builds with nothing to download.

New messages show as one card at the top right, with a bar counting
down to when it closes or sends.

Other changes:
- Steering wheel buttons, knobs and D-pads drive the car screen.
- Smoother car audio: chunks wait for the car instead of dropping.
- Sharper, more responsive video.
- The Gearslip switch in Settings now stops it taking the USB
  connection.
- Apps that refuse Gearslip say so instead of loading forever.
- The phone asks for notification permission.
- The home screen stays upright.
- The car screen shows what's new after an update.

.github/workflows/release.yml

@@ -8,6 +8,8 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - uses: actions/checkout@v4
 
@@ -16,6 +18,8 @@ jobs:
           distribution: temurin
           java-version: "21"
 
+      - uses: gradle/actions/setup-gradle@v4
+
       - name: Write signing key and properties
         run: |
           echo "${{ secrets.KEYSTORE_BASE64 }}" | base64 -d > gearslip-release.jks
@@ -32,7 +36,9 @@ jobs:
       - name: Locate APK
         id: apk
         run: |
-          apk=$(find gearslip/build/outputs/apk/release -name "*.apk" | head -n1)
+          # The build moves its APKs to <root>/build/Gearslip-<variant>.apk (see renameApk).
+          apk=build/Gearslip-release.apk
+          test -f "$apk" || { echo "no APK at $apk"; ls -R build | head -50; exit 1; }
           echo "path=$apk" >> "$GITHUB_OUTPUT"
 
       - name: Create release