feat(assets): standardize asset configuration with capacitor-assets

- Replace manual ImageMagick scripts with official capacitor-assets toolchain
- Consolidate duplicate asset sources to single resources/ directory
- Implement comprehensive asset configuration schema and validation
- Add CI safeguards for asset validation and platform asset detection
- Convert capacitor.config.json to TypeScript format
- Pin Node.js version for deterministic builds
- Remove legacy manual asset generation scripts:
  * generate-icons.sh, generate-ios-assets.sh, generate-android-icons.sh
  * check-android-resources.sh, check-ios-resources.sh
  * purge-generated-assets.sh
- Add new asset management commands:
  * assets:config - generate/update configurations
  * assets:validate - validate configurations
  * assets:clean - clean generated assets (dev only)
  * build:native - build with asset generation
- Create GitHub Actions workflow for asset validation
- Update documentation with new asset management workflow

This standardization eliminates asset duplication, improves build reliability,
and provides a maintainable asset management system using Capacitor defaults.

Breaking Changes: Manual asset generation scripts removed
Migration: Assets now sourced from resources/ directory only
CI: Automated validation prevents committed platform assets

package.json

@@ -25,6 +25,10 @@
     "auto-run:electron": "./scripts/auto-run.sh --platform=electron",
     "build:capacitor": "VITE_GIT_HASH=`git log -1 --pretty=format:%h` vite build --mode capacitor --config vite.config.capacitor.mts",
     "build:capacitor:sync": "npm run build:capacitor && npx cap sync",
+    "build:native": "vite build && npx cap sync && npx capacitor-assets generate",
+    "assets:config": "node scripts/assets-config.js",
+    "assets:validate": "node scripts/assets-validator.js",
+    "assets:clean": "rimraf android/app/src/main/res/mipmap-* ios/App/App/Assets.xcassets/**/AppIcon*.png ios/App/App/Assets.xcassets/**/Splash*.png || true",
     "build:ios": "./scripts/build-ios.sh",
     "build:ios:dev": "./scripts/build-ios.sh --dev",
     "build:ios:test": "./scripts/build-ios.sh --test",