Add reload and restart buttons to Server tab

Adds ability to reload or restart fail2ban service from the Server tab UI.

Backend changes:
- Add new restart() method to jail_service.py that sends 'restart' command
- Add new POST /api/config/restart endpoint in config router
- Endpoint returns 204 on success, 502 if fail2ban unreachable
- Includes structured logging via 'fail2ban_restarted' log entry

Frontend changes:
- Add configRestart endpoint to endpoints.ts
- Add restartFail2Ban() API function in config.ts API module
- Import ArrowSync24Regular icon from Fluent UI
- Add reload and restart button handlers to ServerTab
- Display 'Reload fail2ban' and 'Restart fail2ban' buttons in action row
- Show loading spinner during operation
- Display success/error MessageBar with appropriate feedback
- Update ServerTab docstring to document new buttons

All 115 frontend tests pass.

frontend/src/api/config.ts

@@ -88,7 +88,7 @@ export async function updateGlobalConfig(
 }
 
 // ---------------------------------------------------------------------------
-// Reload
+// Reload and Restart
 // ---------------------------------------------------------------------------
 
 export async function reloadConfig(
@@ -96,6 +96,11 @@ export async function reloadConfig(
   await post<undefined>(ENDPOINTS.configReload, undefined);
 }
 
+export async function restartFail2Ban(
+): Promise<void> {
+  await post<undefined>(ENDPOINTS.configRestart, undefined);
+}
+
 // ---------------------------------------------------------------------------
 // Regex tester
 // ---------------------------------------------------------------------------

frontend/src/api/endpoints.ts

@@ -78,6 +78,7 @@ export const ENDPOINTS = {
   configPendingRecovery: "/config/pending-recovery" as string,
   configGlobal: "/config/global",
   configReload: "/config/reload",
+  configRestart: "/config/restart",
   configRegexTest: "/config/regex-test",
   configPreviewLog: "/config/preview-log",
   configMapColorThresholds: "/config/map-color-thresholds",

frontend/src/components/config/ServerTab.tsx

@@ -2,8 +2,9 @@
  * ServerTab — fail2ban server-level settings editor.
  *
  * Provides form fields for live server settings (log level, log target,
- * DB purge age, DB max matches), a "Flush Logs" action button,
- * world map color threshold configuration, and service health + log viewer.
+ * DB purge age, DB max matches), action buttons (flush logs, reload fail2ban,
+ * restart fail2ban), world map color threshold configuration, and service
+ * health + log viewer.
  */
 
 import { useCallback, useEffect, useMemo, useState } from "react";
@@ -21,6 +22,7 @@ import {
 } from "@fluentui/react-components";
 import {
   DocumentArrowDown24Regular,
+  ArrowSync24Regular,
 } from "@fluentui/react-icons";
 import { ApiError } from "../../api/client";
 import type { ServerSettingsUpdate, MapColorThresholdsResponse, MapColorThresholdsUpdate } from "../../types/config";
@@ -29,6 +31,8 @@ import { useAutoSave } from "../../hooks/useAutoSave";
 import {
   fetchMapColorThresholds,
   updateMapColorThresholds,
+  reloadConfig,
+  restartFail2Ban,
 } from "../../api/config";
 import { AutoSaveIndicator } from "./AutoSaveIndicator";
 import { ServerHealthSection } from "./ServerHealthSection";
@@ -53,6 +57,10 @@ export function ServerTab(): React.JSX.Element {
   const [flushing, setFlushing] = useState(false);
   const [msg, setMsg] = useState<{ text: string; ok: boolean } | null>(null);
 
+  // Reload/Restart state
+  const [isReloading, setIsReloading] = useState(false);
+  const [isRestarting, setIsRestarting] = useState(false);
+
   // Map color thresholds
   const [mapThresholds, setMapThresholds] = useState<MapColorThresholdsResponse | null>(null);
   const [mapThresholdHigh, setMapThresholdHigh] = useState("");
@@ -97,6 +105,38 @@ export function ServerTab(): React.JSX.Element {
     }
   }, [flush]);
 
+  const handleReload = useCallback(async () => {
+    setIsReloading(true);
+    setMsg(null);
+    try {
+      await reloadConfig();
+      setMsg({ text: "fail2ban reloaded successfully", ok: true });
+    } catch (err: unknown) {
+      setMsg({
+        text: err instanceof ApiError ? err.message : "Reload failed.",
+        ok: false,
+      });
+    } finally {
+      setIsReloading(false);
+    }
+  }, []);
+
+  const handleRestart = useCallback(async () => {
+    setIsRestarting(true);
+    setMsg(null);
+    try {
+      await restartFail2Ban();
+      setMsg({ text: "fail2ban restart initiated", ok: true });
+    } catch (err: unknown) {
+      setMsg({
+        text: err instanceof ApiError ? err.message : "Restart failed.",
+        ok: false,
+      });
+    } finally {
+      setIsRestarting(false);
+    }
+  }, []);
+
   // Load map color thresholds on mount.
   const loadMapThresholds = useCallback(async (): Promise<void> => {
     try {
@@ -263,6 +303,22 @@ export function ServerTab(): React.JSX.Element {
           >
             {flushing ? "Flushing…" : "Flush Logs"}
           </Button>
+          <Button
+            appearance="secondary"
+            icon={<ArrowSync24Regular />}
+            disabled={isReloading}
+            onClick={() => void handleReload()}
+          >
+            {isReloading ? "Reloading…" : "Reload fail2ban"}
+          </Button>
+          <Button
+            appearance="secondary"
+            icon={<ArrowSync24Regular />}
+            disabled={isRestarting}
+            onClick={() => void handleRestart()}
+          >
+            {isRestarting ? "Restarting…" : "Restart fail2ban"}
+          </Button>
         </div>
         {msg && (
           <MessageBar intent={msg.ok ? "success" : "error"}>