feat(lxc-updates): revamp Updates + Options card + curated hints

Updates tab
- Unified OS + Application update card with per-section Apply buttons
  and a combined "Apply OS + <app>" footer button
- Helper-scripts install detection: uses helper_slug from managed_installs
  cache (hostname fuzzy-match against helpers_cache) so the button
  surfaces even when /usr/bin/update was removed
- Runs the community-scripts helper INSIDE the CT via pct exec so
  build.func picks the silent update path (PHS_SILENT=1) instead of the
  install menu — works with and without /usr/bin/update
- HELPER_SLUG env passthrough from backend to apply_updates.sh: falls
  back to constructing the ct/<slug>.sh URL when the CT no longer
  carries the marker file
- Post-apply state refresh via managed_installs.check_for_updates(force)
  in the /applied hook so the badge updates without a manual reload

Options card
- Rewrote as view / edit mode split with a single Edit button
- Unified apply defaults (snapshot + storage + restart) shared by
  manual and scheduled runs
- Scheduled updates (M5): cron picker + preset dropdown + What-to-update
  target + Delete schedule button, wired to a background scheduler thread
  that fires apply_updates.sh headless with the schedule's env vars
- External host cron detection with variant + scope reporting
  (tteck-legacy / community-scripts / custom, OS-only), shown as an
  informational chip only in edit mode

App tab editor
- Multi-app registration with per-app upstream tracking method
  (github / http_json / docker_hub)
- Card-contrast pattern in edit mode (bg-card + bg-background inputs)
- Auto-heal for missing installed_version via alt_detectors +
  file_fallbacks

Curated tracking hints (M6)
- Add http_json upstream for Plex (plex.tv API)
- Add binary+github hints for Emby (MediaBrowser/Emby.Releases) and
  PhotoPrism (photoprism/photoprism)
- Extend CI merge whitelist with upstream_type / upstream_url /
  upstream_json_path / docker_image

Tab reorder
- LXC modal tabs: Status | App | Updates | Mounts | Backups | Firewall

apply_updates.sh
- New helper execution path: parse ct/<slug>.sh URL, run inside CT
  with PHS_SILENT=1, respecting HELPER_SLUG fallback when
  /usr/bin/update is missing

AppImage/components/health-status-modal.tsx

@@ -32,7 +32,7 @@ import {
   FileText,
   RefreshCw,
   Shield,
-  Download,
+  ArrowUpCircle,
   X,
   Clock,
   BellOff,
@@ -777,7 +777,7 @@ export function HealthStatusModal({ open, onOpenChange, getApiUrl }: HealthStatu
                               onClick={() => setShowUpdateTerminal(true)}
                               className="bg-purple-600/15 hover:bg-purple-600/25 border border-purple-500/40 text-purple-300 hover:text-purple-200"
                             >
-                              <Download className="h-4 w-4 mr-1.5" />
+                              <ArrowUpCircle className="h-4 w-4 mr-1.5" />
                               {t("healthStatus.updateNow")}
                             </Button>
                           </div>

AppImage/components/ui/input.tsx

@@ -16,7 +16,7 @@ const Input = React.forwardRef<HTMLInputElement, InputProps>(({ className, type,
         // 1px blue ring + matching border so a focused input now sits at the
         // same visual weight as the colored card selectors used elsewhere
         // (Backend picker, etc.).
-        "flex h-10 w-full rounded-lg border border-input bg-background px-4 py-2 text-sm shadow-sm transition-all file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-blue-500 focus-visible:border-blue-500 disabled:cursor-not-allowed disabled:opacity-50 hover:border-ring/50",
+        "flex h-10 w-full rounded-lg border border-input bg-background px-4 py-2 text-sm shadow-sm transition-all file:border-0 file:bg-transparent file:text-sm file:font-medium placeholder:text-muted-foreground placeholder:opacity-40 focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-blue-500 focus-visible:border-blue-500 disabled:cursor-not-allowed disabled:opacity-50 hover:border-ring/50",
         className,
       )}
       ref={ref}

AppImage/components/ui/textarea.tsx

@@ -10,7 +10,7 @@ const Textarea = React.forwardRef<HTMLTextAreaElement, TextareaProps>(
     return (
       <textarea
         className={cn(
-          "flex min-h-[80px] w-full rounded-md border border-input bg-background px-3 py-2 text-sm placeholder:text-muted-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-blue-500 focus-visible:border-blue-500 disabled:cursor-not-allowed disabled:opacity-50",
+          "flex min-h-[80px] w-full rounded-md border border-input bg-background px-3 py-2 text-sm placeholder:text-muted-foreground placeholder:opacity-40 focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-blue-500 focus-visible:border-blue-500 disabled:cursor-not-allowed disabled:opacity-50",
           className
         )}
         ref={ref}