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

docs/index.md

@@ -0,0 +1,36 @@
+---
+# https://vitepress.dev/reference/default-theme-home-page
+layout: home
+
+hero:
+  name: "BentoPDF"
+  text: "Free, Open-Source PDF Tools"
+  tagline: Process PDFs entirely in your browser. No uploads. No servers. Complete privacy.
+  actions:
+    - theme: brand
+      text: Get Started
+      link: /getting-started
+    - theme: alt
+      text: View Tools
+      link: /tools/
+    - theme: alt
+      text: Self-Host
+      link: /self-hosting/
+    - theme: alt
+      text: Commercial License
+      link: /licensing
+
+features:
+  - icon: 🔒
+    title: 100% Private
+    details: Your files never leave your device. All processing happens locally in your browser using WebAssembly.
+  - icon: ⚡
+    title: Fast & Free
+    details: No sign-ups, no limits, no watermarks. Process unlimited PDFs for free, forever.
+  - icon: 🛠️
+    title: 50+ Tools
+    details: Convert, edit, merge, split, compress, sign, OCR, and more. Everything you need in one place.
+  - icon: 🌐
+    title: Self-Hostable
+    details: Deploy on your own infrastructure. Docker, Vercel, Netlify, AWS, or any static hosting.
+---