Rework Dashboard, add toasts, container folders/icons/WebUI links, detail tabs

Dashboard:
- Plain-count stat tiles (Running/Stopped/Pods/Images/Volumes/Networks)
  separated from a single "Resource Usage" card (CPU/Memory/Swap/Storage
  meter rows) instead of forcing both into one tile grid, which produced
  awkward spanning-tile/dead-cell layouts.
- Fixed CPU usage never changing (libpod's own cpuUtilization is computed
  once and never resampled) by computing it from /proc/stat deltas instead.
- Fixed memory usage reading far too high by using /proc/meminfo's
  MemAvailable instead of libpod's raw (non-reclaimable-aware) memFree.
- Added an Autostart Queue table reusing podman-autostart.sh's own
  failure-counter files.
- Dashboard and Containers now auto-refresh every ~2s (paused when the
  tab is hidden or a modal is open).

Toasts:
- Real success/warn/error/info toast notifications replacing every
  alert() used for one-way feedback, across every panel.

Container detail modal:
- 5 new tabs: Resources, Logs, Console, Events, Healthcheck.

Containers panel:
- Folders to group containers (name + icon), stored in the plugin's own
  folders.json — a folder's header always shows an icon+name+status chip
  per member, matching Unraid's own Docker page folders. "Move to
  Folder" becomes "Remove from Folder" once a container is already
  grouped.
- Containers can carry an icon URL and a WebUI URL (small button next to
  the name), both stored as container labels and auto-filled from
  templates where applicable.
- Settings: an "Add container" control for the Autostart order table.

Fixes:
- Context menus now measure their own rendered size and flip above the
  anchor when there isn't room below, instead of running off-screen.
- Containers table now uses table-layout:fixed with explicit column
  widths — auto layout was shifting every column (and the header) on
  every folder expand/collapse, and briefly again when a flex wrapper
  was mistakenly placed directly on a <td>.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

webui/plugins/podman/javascript/networks.js

@@ -164,7 +164,7 @@
       if (!confirm('Remove network "' + name + '"?')) return;
       btn.disabled = true;
       P.post('networks', 'remove', { name: name }).then(load).catch(function (err) {
-        alert('Remove failed: ' + err.message);
+        P.toast('Remove failed: ' + err.message, 'error');
         btn.disabled = false;
       });
     });