Add reproducible build system, native Unraid plugin, and WebUI

- versions.env pins podman, conmon, crun, netavark, aardvark-dns, passt,
  and fuse-overlayfs to verified upstream source checksums; SlackBuild
  recipes, scripts/build-packages.sh, checksums.sh, release.sh, and
  update-versions.sh implement the reproducible pipeline; GitHub Actions
  workflows build in a Slackware container and publish releases without
  committing any binaries.

- plugin/podman.plg installs/updates/removes all eight packages (the
  seven components plus the plugin's own unraid-podman scaffolding
  package) via upgradepkg, using the official Unraid array-event hook
  mechanism (event/disks_mounted, event/stopping) instead of editing
  /boot/config/go. rc.podman and the sbin/ helper scripts implement
  storage creation, config seeding/sync, preflight checks, autostart
  with per-container Safe-Mode, and package verify/update/rollback.

- webui/plugins/podman implements the Dashboard, Containers, Pods,
  Images, Volumes, Networks, Logs, Terminal, Compose, and Settings
  panels against the approved mockup (webui/mockups/prototype.html),
  talking to podman system service exclusively via PodmanClient.php
  (libpod REST API over the Unix socket), with two documented
  exceptions: Terminal's one-shot exec model and Compose's use of the
  podman compose CLI, since libpod has no REST equivalent for either.

- docs/ARCHITECTURE.md and docs/ROADMAP.md record the design decisions
  and honest current status (syntax-checked, unit- and
  integration-tested against fake sockets/servers; not yet run against
  a real Unraid/Podman/Slackware system).

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

webui/plugins/podman/javascript/images.js

@@ -0,0 +1,69 @@
+/**
+ * javascript/images.js
+ *
+ * Images panel: table + a "Pull Image" action, backed by ajax/images.php.
+ */
+(function () {
+  'use strict';
+  const P = window.Podman;
+  let images = [];
+
+  function rowHtml(img) {
+    const created = img.createdAt ? P.formatRelativeTime(img.createdAt) : '—';
+    return '' +
+      '<tr data-id="' + P.escapeHtml(img.id) + '">' +
+      '<td>' + P.escapeHtml(img.repository) + '</td>' +
+      '<td class="mono">' + P.escapeHtml(img.tag) + '</td>' +
+      '<td class="mono podman-row-sub">' + P.escapeHtml(img.shortId) + '</td>' +
+      '<td class="tnum">' + P.escapeHtml(img.sizeFormatted) + '</td>' +
+      '<td class="tnum">' + created + '</td>' +
+      '<td class="tnum">' + img.usedBy + '</td>' +
+      '<td class="podman-actions"><button class="podman-btn podman-btn-icon" data-action="remove"' +
+      (img.usedBy > 0 ? ' disabled title="In use by a container"' : ' title="Remove"') + '>&#128465;</button></td>' +
+      '</tr>';
+  }
+
+  function render() {
+    const tbody = P.el('images-tbody');
+    tbody.innerHTML = images.length
+      ? images.map(rowHtml).join('')
+      : '<tr><td colspan="7" class="podman-empty-note">No images.</td></tr>';
+  }
+
+  function load() {
+    const tbody = P.el('images-tbody');
+    tbody.innerHTML = P.loadingRow(7);
+    return P.get('images', 'list').then(function (data) {
+      images = data;
+      render();
+    }).catch(function (err) {
+      tbody.innerHTML = P.errorRow(7, err.message);
+    });
+  }
+
+  function init() {
+    P.el('images-pull-btn').addEventListener('click', function () {
+      const reference = prompt('Image to pull (e.g. docker.io/library/postgres:16):');
+      if (!reference) return;
+      P.post('images', 'pull', { reference: reference }).then(load).catch(function (err) {
+        alert('Pull failed: ' + err.message);
+      });
+    });
+
+    P.el('images-tbody').addEventListener('click', function (e) {
+      const btn = e.target.closest('button[data-action="remove"]');
+      if (!btn || btn.disabled) return;
+      const id = btn.closest('tr').dataset.id;
+      if (!confirm('Remove this image?')) return;
+      btn.disabled = true;
+      P.post('images', 'remove', { id: id }).then(load).catch(function (err) {
+        alert('Remove failed: ' + err.message);
+        btn.disabled = false;
+      });
+    });
+
+    return load();
+  }
+
+  P.registerPanel('images', { init: init, refresh: load });
+})();