Profil-Seite: Anzeigename, Passwort ändern, Persona (ersetzt USER.md)

- Neuer Menüpunkt 'Mein Profil' statt 'Logout'
- Profil-Page: Anzeigename, Persona (Freitext), Passwort ändern, Logout
- ProfileEndpoint: GET/PUT /api/profile, PUT /api/profile/password
- User-Persona im System-Prompt statt USER.md (Fallback: Anzeigename/Username)
- SystemPromptBuilder: dataDir-Parameter entfernt, userPersona-Parameter hinzugefügt
- DB-Migration: persona-Spalte in users-Tabelle

Services/DatabaseService.cs

@@ -159,6 +159,7 @@ public class DatabaseService
         TryAddColumn(conn, "sessions", "user_id", "TEXT");
         TryAddColumn(conn, "agents", "user_id", "TEXT");
         TryAddColumn(conn, "users", "is_admin", "INTEGER NOT NULL DEFAULT 0");
+        TryAddColumn(conn, "users", "persona", "TEXT");
 
         conn.Execute(@"
             CREATE TABLE IF NOT EXISTS agent_skills (
@@ -733,4 +734,12 @@ public class DatabaseService
             "UPDATE users SET password_hash = @passwordHash, updated_at = @now WHERE user_id = @userId",
             new { userId, passwordHash, now = DateTime.UtcNow.ToString("o") });
     }
+
+    public async Task UpdateUserProfile(string userId, string displayName, string persona)
+    {
+        using var conn = CreateConnection();
+        await conn.ExecuteAsync(
+            "UPDATE users SET display_name = @displayName, persona = @persona, updated_at = @now WHERE user_id = @userId",
+            new { userId, displayName, persona, now = DateTime.UtcNow.ToString("o") });
+    }
 }