Add German localization and styling for administration module

- Introduced new JavaScript file `fis.admin_txt_de.js` for German translations of administration-related terms and messages.
- Created `fis.admin.css` for styling the administration interface, including layout, cards, and buttons.
- Added `fis.admin.de.js` for the main functionality of the administration module, implementing features such as system status checks and email testing.
- Minified version of the German JavaScript file created as `fis.admin.de.min.js`.
- Minified CSS file created as `fis.admin.min.css` for optimized loading.

Fuchs/Controllers/IntranetController.Admin.cs

@@ -0,0 +1,105 @@
+using Fuchs.Services;
+using Microsoft.AspNetCore.Mvc;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
+using OCORE.SQL;
+using static OCORE.SQL.sql;
+using static OCORE.web.mvc_helper_async;
+
+namespace Fuchs.Controllers;
+
+// Partial class: Admin / system-status module.
+//
+// Access is restricted to users whose "fds_sys" module authorization is greater than 4.
+// The menu button is only shown, and the module script only loaded, for such users (frontend),
+// but every data endpoint here ALSO enforces the level server-side (defense in depth) — the
+// passive/probe data is diagnostic and must never be reachable by a lower-privileged session.
+public partial class IntranetController
+{
+    // fds_sys authorization must exceed this to use the Admin module.
+    private const int AdminMinAuthExclusive = 4;
+
+    private async Task<IActionResult> Do_Process_Admin(string fn, string id, string code)
+    {
+        _logger.LogDebug("Do_Process_Admin action={Action} code={Code} user={User}", id, code, UserAccountID);
+
+        // The auth probe is the one endpoint that answers for BOTH authorized and unauthorized
+        // users (the frontend uses manage>0 to decide whether to render the module at all).
+        int authLevel = await GetSystemAdminAuthAsync(fn, id, code);
+        bool authorized = authLevel > AdminMinAuthExclusive;
+
+        if (id.Equals("auth", StringComparison.OrdinalIgnoreCase))
+            return await JSONAsync(new { manage = authorized ? 1 : 0, level = authLevel });
+
+        if (!authorized)
+        {
+            _logger.LogWarning("Admin access denied for user={User} (fds_sys={Level}) action={Action}",
+                UserAccountID, authLevel, id);
+            return Unauthorized401();
+        }
+
+        var status = _systemStatus;
+        switch (id.ToLowerInvariant())
+        {
+            case "status":
+            {
+                var info = status.GetInfo();
+                var probes = await status.ProbeAllAsync(HttpContext.RequestAborted);
+                return AdminJson(new { info, probes });
+            }
+
+            case "info":
+                return AdminJson(new { info = status.GetInfo() });
+
+            case "probe":
+            {
+                // code carries the component id, e.g. /do/admin/probe/database
+                string component = string.IsNullOrWhiteSpace(code) ? Form("component") : code;
+                if (string.IsNullOrWhiteSpace(component))
+                    return BadRequest400();
+                var probe = await status.ProbeAsync(component, HttpContext.RequestAborted);
+                return AdminJson(new { probe });
+            }
+
+            case "testmail":
+            {
+                if (!HasForm("to", "subject"))
+                    return BadRequest400();
+                var result = await status.SendTestEmailAsync(
+                    Form("to"), Form("subject"), Form("body"), HttpContext.RequestAborted);
+                _logger.LogInformation("Admin test email requested by user={User} to={To} sent={Sent}",
+                    UserAccountID, result.RequestedRecipient, result.Sent);
+                return AdminJson(new { result });
+            }
+
+            default:
+                _logger.LogWarning("Admin: no handler for action={Action}, user={User}", id, UserAccountID);
+                return BadRequest400();
+        }
+    }
+
+    // The status DTOs (SystemInfoSnapshot / SystemProbeResult) are PascalCase; serialize them
+    // camelCase so the Admin frontend contract matches the lowercase convention used elsewhere.
+    private static readonly JsonSerializerSettings CamelCaseJson = new()
+    {
+        ContractResolver = new CamelCasePropertyNamesContractResolver(),
+    };
+
+    private ContentResult AdminJson(object payload) =>
+        Content(JsonConvert.SerializeObject(payload, CamelCaseJson), "application/json");
+
+    /// <summary>
+    /// Resolves the calling user's <c>fds_sys</c> module authorization level via the
+    /// <c>fis_getModuleAuth</c> SQL function (same mechanism as <see cref="HandleAuth"/>).
+    /// Returns -3 when it cannot be determined (fail-closed).
+    /// </summary>
+    private async Task<int> GetSystemAdminAuthAsync(string fn, string id, string code)
+    {
+        var val = await getSQLValue_async<int>(
+            "SELECT [dbo].[fis_getModuleAuth](@module, @authuser);",
+            _intranet.Intranet__SQLConnectionString, -3,
+            StdParamlist(SQL_VarChar("@module", "fds_sys")),
+            Security: DbSec, options: SqlOpt(fn, id, code));
+        return val.Result;
+    }
+}

Fuchs/Controllers/IntranetController.cs

@@ -38,6 +38,7 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
     private readonly IInvoiceDraftService _invoiceDrafts;
     private readonly IReminderDraftService _reminderDrafts;
     private readonly IDraftNotifier _draftNotifier;
+    private readonly ISystemStatusService _systemStatus;
     private readonly List<string> _allowedNonAuth = new() { "spwc", "spw" };
     private readonly List<string> _allowedGet = new()
     {
@@ -68,7 +69,8 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
         IEventService events,
         IInvoiceDraftService invoiceDrafts,
         IReminderDraftService reminderDrafts,
-        IDraftNotifier draftNotifier)
+        IDraftNotifier draftNotifier,
+        ISystemStatusService systemStatus)
     {
         _intranet = intranet;
         _mfr = mfr;
@@ -85,6 +87,7 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
         _invoiceDrafts = invoiceDrafts;
         _reminderDrafts = reminderDrafts;
         _draftNotifier = draftNotifier;
+        _systemStatus = systemStatus;
     }
 
     /// <summary>Merged query-string + form parameters (form wins) for report processing.</summary>
@@ -163,6 +166,7 @@ public partial class IntranetController : Microsoft.AspNetCore.Mvc.Controller
                 "rem"     => await Do_Process_Reminder(fn, id, code),
                 "rep"     => await Do_Process_Reports(fn, id, code),
                 "bam"     => await Do_Process_Bankings(fn, id, code),
+                "admin"   => await Do_Process_Admin(fn, id, code),
                 "auth"    => await HandleAuth(fn, id, code),
                 "spwc"    => await HandleSendPasswordCode(fn, id, code),
                 "spw"     => await HandleSendPassword(fn, id, code),