Fix Failures tooltip wording; move Service Health to top of Server tab

Task 2: rename 'Failures:' label to 'Failed Attempts:' and update tooltip
to 'Total failed authentication attempts currently tracked by fail2ban
across all active jails' — more accurate than 'Currently failing IPs'.

Task 3: move <ServerHealthSection /> to the top of ServerTab so users
see connectivity status before scrolling through all settings fields.

frontend/src/components/config/ServerTab.tsx

@@ -219,6 +219,10 @@ export function ServerTab(): React.JSX.Element {
 
   return (
     <div>
+      {/* Service Health & Log Viewer section — shown first so users can
+          immediately see whether fail2ban is reachable before editing settings. */}
+      <ServerHealthSection />
+
       <div className={styles.sectionCard}>
         <div style={{ marginBottom: tokens.spacingVerticalS }}>
           <AutoSaveIndicator
@@ -412,8 +416,6 @@ export function ServerTab(): React.JSX.Element {
         </div>
       ) : null}
 
-      {/* Service Health & Log Viewer section */}
-      <ServerHealthSection />
     </div>
   );
 }