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/build.mjs

@@ -0,0 +1,92 @@
+/**
+ * Build script for ProxmoxPanel Alpine frontend.
+ * - Bundles Swup into an IIFE (browser-loadable)
+ * - Bundles xterm.js + addon-fit into IIFEs
+ * - Copies all static assets to dist/
+ */
+
+import * as esbuild from 'esbuild'
+import * as fs from 'fs'
+import * as path from 'path'
+
+const dist = 'dist'
+
+// Clean dist
+fs.rmSync(dist, { recursive: true, force: true })
+fs.mkdirSync(`${dist}/js/vendors`, { recursive: true })
+fs.mkdirSync(`${dist}/js`, { recursive: true })
+fs.mkdirSync(`${dist}/css`, { recursive: true })
+fs.mkdirSync(`${dist}/locales`, { recursive: true })
+
+// 1. Bundle Swup into IIFE
+console.log('Bundling Swup...')
+await esbuild.build({
+  entryPoints: ['swup-bundle.entry.mjs'],
+  bundle: true,
+  format: 'iife',
+  globalName: '_swupExports',
+  outfile: `${dist}/js/vendors/swup.iife.js`,
+  minify: true,
+})
+// Expose Swup on window
+const swupOut = fs.readFileSync(`${dist}/js/vendors/swup.iife.js`, 'utf8')
+fs.writeFileSync(`${dist}/js/vendors/swup.iife.js`,
+  swupOut + '\nwindow.Swup=_swupExports.Swup;')
+
+// 2. Bundle xterm.js
+console.log('Bundling xterm...')
+await esbuild.build({
+  entryPoints: ['xterm-bundle.entry.mjs'],
+  bundle: true,
+  format: 'iife',
+  globalName: '_xtermExports',
+  outfile: `${dist}/js/vendors/xterm.iife.js`,
+  minify: true,
+})
+const xtermOut = fs.readFileSync(`${dist}/js/vendors/xterm.iife.js`, 'utf8')
+fs.writeFileSync(`${dist}/js/vendors/xterm.iife.js`,
+  xtermOut + '\nwindow.Terminal=_xtermExports.Terminal;window.FitAddon=_xtermExports.FitAddon;')
+
+// xterm CSS
+const xtermCss = 'node_modules/@xterm/xterm/css/xterm.css'
+if (fs.existsSync(xtermCss)) {
+  fs.copyFileSync(xtermCss, `${dist}/css/xterm.css`)
+}
+
+// 3. Copy pre-downloaded vendors (Alpine, HTMX)
+for (const f of ['alpine.min.js', 'htmx.min.js']) {
+  const src = `vendors/${f}`
+  if (fs.existsSync(src)) {
+    fs.copyFileSync(src, `${dist}/js/vendors/${f}`)
+    console.log(`Copied ${f}`)
+  } else {
+    console.warn(`WARN: ${src} not found`)
+  }
+}
+
+// 4. Copy app JS files
+for (const f of fs.readdirSync('js')) {
+  if (f.endsWith('.js')) {
+    fs.mkdirSync(`${dist}/js`, { recursive: true })
+    fs.copyFileSync(`js/${f}`, `${dist}/js/${f}`)
+  }
+}
+
+// 5. Copy CSS
+for (const f of fs.readdirSync('css')) {
+  fs.copyFileSync(`css/${f}`, `${dist}/css/${f}`)
+}
+
+// 6. Copy locales
+for (const f of fs.readdirSync('locales')) {
+  fs.copyFileSync(`locales/${f}`, `${dist}/locales/${f}`)
+}
+
+// 7. Copy HTML pages
+for (const f of fs.readdirSync('.')) {
+  if (f.endsWith('.html')) {
+    fs.copyFileSync(f, `${dist}/${f}`)
+  }
+}
+
+console.log('✓ Build complete → dist/')