Add ignore-self toggle to Jail Detail page

Implements the missing UI control for POST /api/jails/{name}/ignoreself:
- Add jailIgnoreSelf endpoint constant to endpoints.ts
- Add toggleIgnoreSelf(name, on) API function to jails.ts
- Expose toggleIgnoreSelf action from useJailDetail hook
- Replace read-only 'ignore self' badge with a Fluent Switch in
  IgnoreListSection to allow enabling/disabling the flag per jail
- Add 5 vitest tests for checked/unchecked state and toggle behaviour

frontend/src/api/endpoints.ts

@@ -45,6 +45,7 @@ export const ENDPOINTS = {
   jailReload: (name: string): string => `/jails/${encodeURIComponent(name)}/reload`,
   jailsReloadAll: "/jails/reload-all",
   jailIgnoreIp: (name: string): string => `/jails/${encodeURIComponent(name)}/ignoreip`,
+  jailIgnoreSelf: (name: string): string => `/jails/${encodeURIComponent(name)}/ignoreself`,
 
   // -------------------------------------------------------------------------
   // Bans

frontend/src/api/jails.ts

@@ -149,6 +149,24 @@ export async function delIgnoreIp(
   return del<JailCommandResponse>(ENDPOINTS.jailIgnoreIp(name), { ip });
 }
 
+/**
+ * Enable or disable the `ignoreself` flag for a jail.
+ *
+ * When enabled, fail2ban automatically adds the server's own IP addresses to
+ * the ignore list so the host can never ban itself.
+ *
+ * @param name - Jail name.
+ * @param on   - `true` to enable, `false` to disable.
+ * @returns A {@link JailCommandResponse} confirming the change.
+ * @throws {ApiError} On non-2xx responses.
+ */
+export async function toggleIgnoreSelf(
+  name: string,
+  on: boolean,
+): Promise<JailCommandResponse> {
+  return post<JailCommandResponse>(ENDPOINTS.jailIgnoreSelf(name), on);
+}
+
 // ---------------------------------------------------------------------------
 // Ban / unban
 // ---------------------------------------------------------------------------