Settings: collapse advanced sections + dedicated About + default DB name

- DB default name: "proserve" → "proserveapi" (matches the ASTERION install
  script that provisions XAMPP on client machines).
- Settings dialog reorganized:
   1. License de mise à jour     [expanded] ← business-critical
   2. Langue                     [expanded] ← user preference
   3. ▸ PARAMÈTRES AVANCÉS       [collapsed by default]
        contains Server, Installation, Cache, Database, Logs
   4. À PROPOS                   [expanded] ← version + copyright
- The Expander hides plumbing the casual user shouldn't touch (server URL,
  install root, MySQL config, cache directory) but keeps it one click away
  for power users / support diagnostics.
- About card kept always-visible because version info is what support asks
  for first when troubleshooting.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/PSLauncher.Models/LocalConfig.cs

@@ -57,9 +57,11 @@ public sealed class DatabaseConfig
 
     /// <summary>
     /// Nom de la base de données qui contient les tables de PROSERVE.
-    /// Default "proserve" — change si ton install crée la DB sous un autre nom.
+    /// Default "proserveapi" — c'est le nom utilisé par le script d'install ASTERION
+    /// qui provisionne XAMPP sur les machines clients. À surcharger seulement si la DB
+    /// a été créée sous un autre nom.
     /// </summary>
-    public string Database { get; set; } = "proserve";
+    public string Database { get; set; } = "proserveapi";
 
     /// <summary>
     /// Si true, le launcher applique automatiquement les migrations SQL bundled