feat(pwa): favicon, maskable icon, splash screens, runtime cache, safe-area insets

- Add favicon.ico, favicon-32x32.png, favicon-16x16.png
- Add dedicated maskable-512x512.png with safe-zone padding for Android adaptive icons
- Add iOS splash screens for 5 common device sizes (excluded from SW precache)
- Add NetworkFirst runtime caching for stable API routes (excludes volatile endpoints)
- Add safe-top inset to all view headers for PWA standalone mode
- Bump version to 0.2.2

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@kuannnn/clawtap",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "Mobile UI for AI coding assistants. Real-time sync with Claude Code, Codex CLI, and Gemini CLI via tmux.",
   "type": "module",
   "bin": {