feat: réécriture frontend Alpine.js + HTMX + Swup (branche frontend/alpine)

Remplace Vue 3 / Vite / TypeScript par une stack légère statique :
- Alpine.js v3 : réactivité inline, stores auth/ui/i18n, composants par page
- HTMX v2 : interactions serveur via attributs HTML
- Swup v4 : transitions de page (bundlé via esbuild, IIFE browser-loadable)
- xterm.js v5 : terminal PTY (bundlé via esbuild)

Structure : HTML statiques + js/app.js + js/terminal.js + css/ + locales/
Build : esbuild (bundle Swup + xterm seulement) → dist/ → Nginx
Dockerfile simplifié : node:22-alpine build → nginx:1.27-alpine serve

Pages : index, install, login, dashboard, proxmox, updates, terminal, settings, modules
URLs propres via nginx try_files $uri.html

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/package.json

@@ -1,37 +1,15 @@
 {
   "name": "proxmoxpanel-frontend",
-  "version": "1.0.0",
+  "version": "2.0.0",
   "private": true,
+  "type": "module",
   "scripts": {
-    "dev": "vite",
-    "build": "vue-tsc --noEmit && vite build",
-    "preview": "vite preview"
-  },
-  "dependencies": {
-    "vue": "^3.5.13",
-    "vue-router": "^4.5.0",
-    "pinia": "^2.3.0",
-    "vue-i18n": "^11.0.0",
-    "@xterm/xterm": "^5.5.0",
-    "@xterm/addon-fit": "^0.10.0",
-    "@xterm/addon-attach": "^0.11.0",
-    "@codemirror/state": "^6.5.1",
-    "@codemirror/view": "^6.36.3",
-    "@codemirror/commands": "^6.8.0",
-    "@codemirror/language": "^6.10.8",
-    "@codemirror/lang-javascript": "^6.2.2",
-    "@codemirror/lang-json": "^6.0.1",
-    "@codemirror/lang-css": "^6.3.1",
-    "@codemirror/lang-html": "^6.4.10",
-    "@codemirror/lang-python": "^6.1.7",
-    "@codemirror/lang-markdown": "^6.3.2",
-    "@codemirror/theme-one-dark": "^6.1.2",
-    "vue-draggable-plus": "^0.6.0"
+    "build": "node build.mjs"
   },
   "devDependencies": {
-    "@vitejs/plugin-vue": "^5.2.1",
-    "typescript": "^5.7.3",
-    "vite": "^6.3.3",
-    "vue-tsc": "^2.2.10"
+    "swup": "^4.8.0",
+    "@xterm/xterm": "^5.5.0",
+    "@xterm/addon-fit": "^0.10.0",
+    "esbuild": "^0.24.0"
   }
 }