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/include/PodmanClient.php

@@ -185,6 +185,41 @@ final class PodmanClient
         return self::demuxStream($raw);
     }
 
+    /**
+     * GET /events?stream=false&since=...&filters={"container":["<id>"]} —
+     * a bounded, already-happened event history for one container, NOT a
+     * live stream (stream=false makes libpod return what already matched
+     * and close the connection immediately, verified live). This is
+     * enough for a container's "Events" detail tab without needing the
+     * persistent-connection event-streaming infrastructure a live,
+     * fleet-wide event feed would require (see dashboard.js's own header
+     * comment on why that's out of scope for now).
+     *
+     * @return array<int,array<string,mixed>>
+     */
+    public function containerEvents(string $id, int $sinceUnixSeconds): array
+    {
+        $query = [
+            'stream' => 'false',
+            'since' => (string) $sinceUnixSeconds,
+            'filters' => json_encode(['container' => [$id]]),
+        ];
+        $raw = $this->requestRaw('GET', '/events', $query);
+        // Newline-delimited JSON, not a single JSON array — each line is
+        // its own event object.
+        $events = [];
+        foreach (explode("\n", trim($raw)) as $line) {
+            if ($line === '') {
+                continue;
+            }
+            $decoded = json_decode($line, true);
+            if (is_array($decoded)) {
+                $events[] = $decoded;
+            }
+        }
+        return $events;
+    }
+
     // -------------------------------------------------------------------
     // Exec — see webui/plugins/podman/ajax/exec.php for the important
     // caveat: this implements one-shot "run a command, return its output"