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.

gearslip/src/main/res/drawable/voice_selection_24.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="960"
+    android:viewportHeight="960">
+  <path
+      android:fillColor="#FF000000"
+      android:pathData="M80,880L80,800Q126,800 171,794Q216,788 259,772Q259,772 259,772Q259,772 259,772Q213,749 186.5,705.5Q160,662 160,611L160,520L320,520Q320,520 320,520Q320,520 320,520L320,400L455,400Q455,400 455,400Q455,400 455,400L324,138L396,102L527,364Q547,404 524,442Q501,480 456,480L400,480L400,520Q400,553 376.5,576.5Q353,600 320,600L240,600L240,611Q240,646 261.5,672.5Q283,699 316,708L328,711Q368,721 373,761Q378,801 342,821Q282,854 215.5,867Q149,880 80,880ZM652,766L595,710Q616,689 628,661.5Q640,634 640,602Q640,570 628,542.5Q616,515 595,494L652,437Q684,469 702,511.5Q720,554 720,602Q720,650 702,692Q684,734 652,766ZM765,880L708,823Q751,780 775.5,723.5Q800,667 800,602Q800,536 775.5,480Q751,424 708,381L765,324Q819,378 849.5,449Q880,520 880,602Q880,683 849.5,754.5Q819,826 765,880Z"/>
+</vector>

gearslip/src/main/res/drawable/volume_up_24.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+  <path
+      android:fillColor="#FF000000"
+      android:pathData="M3,9v6h4l5,5V4L7,9H3zM16.5,12c0,-1.77 -1.02,-3.29 -2.5,-4.03v8.05c1.48,-0.73 2.5,-2.25 2.5,-4.02zM14,3.23v2.06c2.89,0.86 5,3.54 5,6.71s-2.11,5.85 -5,6.71v2.06c4.01,-0.91 7,-4.49 7,-8.77s-2.99,-7.86 -7,-8.77z"/>
+</vector>