feat: complete UI redesign with DaisyUI + Tailwind CSS v4

Design system overhaul using DaisyUI v5 on Tailwind CSS v4:

- Custom 'ohmstream' dark theme with orange primary (#FF9F1C),
  magenta secondary, gold accent matching existing palette
- Tailwind CSS-first config (input.css source, style.css built output)
- DaisyUI components: navbar, drawer, cards, badges, alerts, tables,
  progress bars, tabs, toggles, stats, form controls, tooltips
- Mobile-first responsive layout with drawer navigation
- Eliminated ~500+ lines of embedded CSS across 15+ template files
- Removed all inline style spam from admin_panel and settings_section
- Preserved all HTMX triggers, Alpine.js state, and Jinja2 logic
- Updated auth-ui.js for DaisyUI tab-active class compatibility

Build: npm run build:css (minified) / npm run watch:css (dev)

templates/components/downloads_section.html

@@ -1,15 +1,18 @@
-<div class="section-container">
-    <div class="section-header">
-        <h2>Telechargements <span id="activeDownloadsCount" class="active-downloads-counter" style="display:none;">(0 actif)</span></h2>
-        <div class="header-actions">
-            <button class="btn btn-sm btn-secondary" 
+<div class="mb-10">
+    <div class="flex justify-between items-center mb-4">
+        <h2 class="text-xl font-bold flex items-center gap-2">
+            Téléchargements
+            <span id="activeDownloadsCount" class="badge badge-primary badge-sm" style="display:none;">0 actif</span>
+        </h2>
+        <div class="flex gap-2">
+            <button class="btn btn-sm btn-ghost" 
                     hx-post="/api/downloads/cleanup" 
                     hx-swap="none"
                     hx-confirm="Nettoyer tous les telechargements termines ?"
                     hx-on::after-request="htmx.trigger('#downloads-container-inner', 'refresh')">
                 <i class="fas fa-broom"></i> Nettoyer termines
             </button>
-            <button class="btn btn-sm btn-danger" 
+            <button class="btn btn-sm btn-error" 
                     hx-post="/api/downloads/cancel-all" 
                     hx-swap="none"
                     hx-confirm="Annuler tous les telechargements actifs ?"
@@ -23,22 +26,9 @@
     <div id="downloads-container-inner" 
          hx-get="/api/downloads?html=1" 
          hx-trigger="load, refresh, every 3s" 
-         hx-swap="innerHTML">
-        <div class="loading-placeholder">
-            <div class="spinner"></div> Chargement des telechargements...
-        </div>
+         hx-swap="innerHTML"
+         class="flex justify-center py-8 text-base-content/50">
+        <span class="loading loading-spinner loading-lg"></span>
+        <span class="ml-2">Chargement des telechargements...</span>
     </div>
 </div>
-
-<style>
-.section-container { margin-bottom: 40px; }
-.active-downloads-counter {
-    font-size: 0.85rem;
-    font-weight: 600;
-    color: var(--primary);
-    background: rgba(241, 80, 37, 0.1);
-    padding: 2px 10px;
-    border-radius: 12px;
-    margin-left: 10px;
-}
-</style>