Swap app icon to the v3 design (record button + transcript mic)

- new icon source in icon/ (make_icon_v3.py + masters): near-black
  gradient tile, red record button with white bezel, mic capsule as a
  transcript card with red lines and a cursor
- Android: adaptive icon uses the 512px master as the full-bleed
  background layer (launcher masks crop it to shape) with a transparent
  foreground; old vector foreground and launcher color removed
- desktop: hicolor PNGs replaced at 32-512 px (48 regenerated from the
  master), old SVG removed; install.sh picks them up unchanged
- APK installed on the Fairphone; aapt2 confirms the adaptive icon

share/icons/hicolor/scalable/apps/meetrec.svg

@@ -1,26 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<svg width="128" height="128" viewBox="0 0 128 128" xmlns="http://www.w3.org/2000/svg">
-  <title>MeetRec</title>
-  <defs>
-    <linearGradient id="bg" x1="0" y1="0" x2="0" y2="1">
-      <stop offset="0" stop-color="#e74c3c"/>
-      <stop offset="1" stop-color="#922b21"/>
-    </linearGradient>
-  </defs>
-
-  <rect x="4" y="4" width="120" height="120" rx="28" fill="url(#bg)"/>
-
-  <!-- microphone: capsule + cradle -->
-  <rect x="50" y="18" width="28" height="42" rx="14" fill="#ffffff"/>
-  <path d="M 36 48 v 8 a 28 28 0 0 0 56 0 v -8"
-        fill="none" stroke="#ffffff" stroke-width="9" stroke-linecap="round"/>
-
-  <!-- waveform: voice becoming transcript -->
-  <g fill="#ffffff">
-    <rect x="32" y="96" width="8" height="14" rx="4"/>
-    <rect x="46" y="91" width="8" height="24" rx="4"/>
-    <rect x="60" y="95" width="8" height="16" rx="4"/>
-    <rect x="74" y="91" width="8" height="24" rx="4"/>
-    <rect x="88" y="96" width="8" height="14" rx="4"/>
-  </g>
-</svg>