Remove RecoveryBanner component and dead onCrashDetected code

- Delete RecoveryBanner.tsx component and its test
- Remove RecoveryBanner from MainLayout
- Remove onCrashDetected prop from ActivateJailDialog, JailsTab
- Remove fetchPendingRecovery, rollbackJail API functions
- Remove configJailRollback, configPendingRecovery endpoints
- Remove PendingRecovery type

frontend/src/components/config/ActivateJailDialog.tsx

@@ -5,12 +5,8 @@
  * findtime, maxretry, port and logpath.  Calls the activate endpoint on
  * confirmation and propagates the result via callbacks.
  *
- * Task 3 additions:
- *  - Runs pre-activation validation when the dialog opens and displays any
- *    warnings or blocking errors before the user confirms.
- *  - Extended spinner text during the post-reload probe phase.
- *  - Calls `onCrashDetected` when the activation response signals that
- *    fail2ban stopped responding after the reload.
+ * Runs pre-activation validation when the dialog opens and displays any
+ * warnings or blocking errors before the user confirms.
  */
 
 import { useEffect, useState } from "react";
@@ -52,11 +48,6 @@ export interface ActivateJailDialogProps {
   onClose: () => void;
   /** Called after the jail has been successfully activated. */
   onActivated: () => void;
-  /**
-   * Called when fail2ban stopped responding after the jail was activated.
-   * The recovery banner will surface this to the user.
-   */
-  onCrashDetected?: () => void;
 }
 
 // ---------------------------------------------------------------------------
@@ -77,7 +68,6 @@ export function ActivateJailDialog({
   open,
   onClose,
   onActivated,
-  onCrashDetected,
 }: ActivateJailDialogProps): React.JSX.Element {
   const [bantime, setBantime] = useState("");
   const [findtime, setFindtime] = useState("");
@@ -173,9 +163,6 @@ export function ActivateJailDialog({
           setValidationWarnings(result.validation_warnings);
         }
         resetForm();
-        if (!result.fail2ban_running) {
-          onCrashDetected?.();
-        }
         onActivated();
       })
       .catch((err: unknown) => {
@@ -339,9 +326,10 @@ export function ActivateJailDialog({
                 style={{ marginTop: tokens.spacingVerticalS }}
               >
                 <MessageBarBody>
-                  <MessageBarTitle>Activation Failed — System Recovered</MessageBarTitle>
-                  Activation of jail &ldquo;{jail.name}&rdquo; failed. The server
-                  has been automatically recovered.
+                  <MessageBarTitle>Activation Failed — Configuration Rolled Back</MessageBarTitle>
+                  The configuration for jail &ldquo;{jail.name}&rdquo; has been
+                  rolled back to its previous state and fail2ban is running
+                  normally. Review the configuration and try activating again.
                 </MessageBarBody>
               </MessageBar>
             )}
@@ -351,10 +339,12 @@ export function ActivateJailDialog({
                 style={{ marginTop: tokens.spacingVerticalS }}
               >
                 <MessageBarBody>
-                  <MessageBarTitle>Activation Failed — Manual Intervention Required</MessageBarTitle>
-                  Activation of jail &ldquo;{jail.name}&rdquo; failed and
-                  automatic recovery was unsuccessful. Manual intervention is
-                  required.
+                  <MessageBarTitle>Activation Failed — Rollback Unsuccessful</MessageBarTitle>
+                  Activation of jail &ldquo;{jail.name}&rdquo; failed and the
+                  automatic rollback did not complete. The file{" "}
+                  <code>jail.d/{jail.name}.local</code> may still contain{" "}
+                  <code>enabled = true</code>. Check the fail2ban logs, correct
+                  the file manually, and restart fail2ban.
                 </MessageBarBody>
               </MessageBar>
             )}