feat(icons): implement shared SVG icon system across packages

- Create centralized SVG files in core icons package assets directory
- Add rollup-plugin-string to core icons for SVG file processing
- Export SVG_ICONS object from core package for cross-package sharing
- Refactor html-icons to import SVG strings from @vjs-10/icons
- Remove hardcoded SVG strings in favor of shared definitions
- Add TypeScript declarations for SVG imports

This establishes a foundation for sharing more code across the monorepo
while maintaining proper package boundaries and build system integration.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

packages/html/html-icons/src/media-pause-icon.ts

@@ -1,11 +1,10 @@
 import { MediaChromeIcon } from './media-chrome-icon.js';
+import { SVG_ICONS } from '@vjs-10/icons';
 
 export function getTemplateHTML() {
   return /* html */ `
     ${MediaChromeIcon.getTemplateHTML()}
-    <svg viewBox="0 0 24 24">
-      <path d="M6 19h4V5H6v14zm8-14v14h4V5h-4z"/>
-    </svg>
+    ${SVG_ICONS.pause}
   `;
 }