Fix H3/L30/L44/L60/L90/L25/L32 polish: dependencies, naming, consistency

L30: Remove redundant loading=lazy from MediaThumb images inside the
     virtualizer which only mounts visible rows anyway.
L44: electron-builder.yml now excludes the actual eslint.config.js and
     .prettierrc rather than non-existent legacy .eslintrc/.prettierrc.yaml.
L60: IpcChannels.externalUrl renamed from external-url to app:external-url
     to match every other channel name category prefix.
L90: settings.ts sanitizeOptions now uses (ARR as readonly string[]).includes
     pattern consistently with setSettings; removes the as-never hack.

typecheck + 242 tests + eslint + prettier green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

electron-builder.yml

@@ -23,7 +23,7 @@ files:
   - '!**/.vscode/*'
   - '!src/*'
   - '!electron.vite.config.{js,ts,mjs,cjs}'
-  - '!{.eslintignore,.eslintrc.cjs,.eslintrc.js,.prettierignore,.prettierrc.yaml,dev-app-update.yml,CHANGELOG.md,README.md}'
+  - '!{eslint.config.js,.prettierrc,dev-app-update.yml,CHANGELOG.md,README.md}'
   - '!{.env,.env.*,.npmrc,pnpm-lock.yaml,package-lock.json}'
   - '!{tsconfig.json,tsconfig.node.json,tsconfig.web.json}'
   - '!*.tsbuildinfo'