feat: add VitePress docs site, music file picker modal, Dockerfile optimization, i18n keys for 14 locales

- Add docs/ with VitePress site (19 pages): guide, config, architecture, FAQ
- Add GitHub Actions workflow for auto-deploy to GitHub Pages
- Replace music 'Add Tracks' upload picker with in-app audio file browser modal
- Add music picker CSS styles with dark theme support
- Add missing i18n keys (search_audio, no_audio_files, etc.) to all 14 locales
- Optimize Dockerfile: shared base stage, COPY --chmod, consolidated RUN, HEALTHCHECK
- Improve README: docs links, updated stats (222+ tests, 14 languages), feature status

docs/index.md

@@ -0,0 +1,41 @@
+---
+layout: home
+
+hero:
+  name: "OxiCloud"
+  text: "Self-hosted cloud storage"
+  tagline: "Files, calendar & contacts — blazingly fast, written in Rust"
+  image:
+    src: /logo.svg
+    alt: OxiCloud Logo
+  actions:
+    - theme: brand
+      text: Get Started
+      link: /guide/installation
+    - theme: alt
+      text: View on GitHub
+      link: https://github.com/DioCrafts/OxiCloud
+    - theme: alt
+      text: Why OxiCloud?
+      link: /guide/
+
+features:
+  - icon: 🚀
+    title: Blazingly Fast
+    details: Single Rust binary, ~40 MB Docker image, <1s cold start, 30–50 MB idle RAM.
+  - icon: 📁
+    title: Full File Management
+    details: Chunked uploads, SHA-256 deduplication, trash, favourites, full-text search, thumbnails.
+  - icon: 🔗
+    title: WebDAV / CalDAV / CardDAV
+    details: RFC-compliant protocols for files, calendars, and contacts. Works with all major clients.
+  - icon: 📝
+    title: Office Editing (WOPI)
+    details: Edit documents in Collabora Online or OnlyOffice directly in the browser.
+  - icon: 🔐
+    title: Security First
+    details: JWT + Argon2id, OIDC/SSO (Keycloak, Authentik, Azure AD), role-based access, shared links.
+  - icon: 🌍
+    title: 14 Languages
+    details: EN, ES, DE, FR, IT, PT, NL, ZH, JA, KO, AR, HI, FA, RU — and growing.
+---