feat(desktop): add offline cache and verified app updates

Clean release notes in Android and desktop update dialogs. Persist downloaded audio and offline playback events per server and user; add desktop update checks, checksum verification and installer launch.

packages/core/src/index.ts

@@ -29,3 +29,4 @@ export { initialWaveState, mix, rgb, rgba, step, WAVE_COLORS, wavePalette, waveS
 export { WaveCoordinator, EARLY_SKIP_MS, WAVE_REFILL_AT, type WaveInfo, type WaveOutcome, type WaveFeedback, type WaveGateway } from './wave';
 
 export { AGE_GROUPS, GENDERS } from './onboarding';
+export { releaseNotesText } from './releases';

packages/core/src/releases.test.ts

@@ -0,0 +1,12 @@
+import { describe, expect, it } from 'vitest';
+import { releaseNotesText } from './releases';
+
+describe('release notes', () => {
+  it('removes build reports from all platforms, preserving real changes', () => {
+    expect(releaseNotesText('<!-- android-status -->\n> APK `file.apk` SHA-256: abc\n<!-- /android-status -->\n\n<!-- desktop-linux-status -->\n> package.deb\n<!-- /desktop-linux-status -->\n\n## Changes\n- **Offline** [playback](https://example.com)\n- Fix `player`')).toBe('Changes\n• Offline playback\n• Fix player');
+  });
+  it('hides comments and handles releases containing only build reports', () => {
+    expect(releaseNotesText('<!-- android-status -->\n> build\n<!-- /android-status -->')).toBe('');
+    expect(releaseNotesText('<!-- internal -->\n> Hello\n\n\nWorld')).toBe('Hello\n\nWorld');
+  });
+});

packages/core/src/releases.ts

@@ -0,0 +1,16 @@
+/** Release bodies also contain CI build reports; these are not user-facing notes. */
+export function releaseNotesText(markdown: string): string {
+  return markdown
+    .replace(/<!--\s*([\w-]+-status)\s*-->[\s\S]*?<!--\s*\/\1\s*-->/gi, '')
+    .replace(/<!--[\s\S]*?-->/g, '')
+    .replace(/^\s*```[^\n]*\n[\s\S]*?^\s*```\s*$/gm, '')
+    .replace(/^\s{0,3}#{1,6}\s+/gm, '')
+    .replace(/^\s*>\s?/gm, '')
+    .replace(/!\[([^\]]*)\]\([^)]*\)/g, '$1')
+    .replace(/\[([^\]]+)\]\([^)]*\)/g, '$1')
+    .replace(/(`+)(.*?)\1/g, '$2')
+    .replace(/\*\*(.*?)\*\*|__(.*?)__/g, '$1$2')
+    .replace(/^\s*[-*+]\s+/gm, '• ')
+    .replace(/\n{3,}/g, '\n\n')
+    .trim();
+}