feat: Add VitePress docs, EPUB to PDF tool, Phosphor icons, and licensing updates

- Set up VitePress documentation site (docs:dev, docs:build, docs:preview)
- Added Getting Started, Tools Reference, Contributing, and Commercial License pages
- Created self-hosting guides for Docker, Vercel, Netlify, Cloudflare, AWS, Hostinger, Nginx, Apache
- Updated README with documentation link, sponsors section, and docs contribution guide

- Added EPUB to PDF converter using LibreOffice WASM

- Migrated to Phosphor Icons for consistent iconography

- Added donation ribbon banner on landing page
- Removed 'Like My Work?' section (replaced by ribbon)
- Updated licensing.html with delivery model, AGPL notice, invoicing, and no-refund policy

- Added Commercial License documentation page
- Updated translations table (Chinese added, marked non-English as In Progress)

- Added sponsors.yml workflow for auto-generating sponsor avatars

src/pages/heic-to-pdf.html

@@ -97,8 +97,8 @@
                     <i data-lucide="plus"></i> <span data-i18n="upload.addMore">Add More Files</span>
                 </button>
                 <button id="clear-files-btn"
-                    class="btn bg-red-600 hover:bg-red-700 text-white font-semibold px-4 py-2 rounded-lg flex items-center gap-2">
-                    <i data-lucide="x"></i> <span data-i18n="upload.clearAll">Clear All</span>
+                    class="btn bg-gray-700 hover:bg-gray-600 text-white font-semibold px-4 py-2 rounded-lg flex items-center gap-2">
+                    <i data-lucide="trash-2"></i> <span data-i18n="upload.clearAll">Clear All</span>
                 </button>
             </div>