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/terminal.js

@@ -0,0 +1,89 @@
+/**
+ * javascript/terminal.js
+ *
+ * Terminal panel: one-command-at-a-time exec via ajax/exec.php. See that
+ * file's header comment for the full, honest explanation of why this is
+ * "type a command, see its output" rather than a true interactive PTY —
+ * the short version is that libpod's interactive exec needs a persistent
+ * bidirectional connection this PHP/AJAX stack doesn't have, and faking
+ * interactivity on top of that would break the moment a user ran anything
+ * that expects a real terminal (vim, an interactive prompt, etc).
+ *
+ * `cd` is handled client-side: this module tracks a per-session `cwd` and
+ * passes it as the exec's working directory on every call, so at least
+ * directory navigation feels persistent even though nothing else is.
+ */
+(function () {
+  'use strict';
+  const P = window.Podman;
+  let cwd = '/';
+  let containerId = null;
+
+  function appendLine(html) {
+    const out = P.el('term-output');
+    const div = document.createElement('div');
+    div.innerHTML = html;
+    out.appendChild(div);
+    out.scrollTop = out.scrollHeight;
+  }
+
+  function promptHtml() {
+    return '<span class="prompt">root</span>:<span class="path">' + P.escapeHtml(cwd) + '</span>$';
+  }
+
+  function runCommand(cmd) {
+    appendLine(promptHtml() + ' ' + P.escapeHtml(cmd));
+
+    // `cd <dir>` is intercepted client-side (see file header) rather than
+    // sent as a real command, since a one-shot exec has no way to report
+    // "the working directory changed" back to us otherwise.
+    const cdMatch = cmd.trim().match(/^cd\s+(\S+)$/);
+    if (cdMatch) {
+      cwd = cdMatch[1].startsWith('/') ? cdMatch[1] : (cwd.replace(/\/$/, '') + '/' + cdMatch[1]);
+      return Promise.resolve();
+    }
+
+    return P.post('exec', 'run', { id: containerId, cmd: cmd, cwd: cwd }).then(function (data) {
+      if (data.output) appendLine('<span class="mono">' + P.escapeHtml(data.output).replace(/\n/g, '<br>') + '</span>');
+    }).catch(function (err) {
+      appendLine('<span style="color:#ef6470;">' + P.escapeHtml(err.message) + '</span>');
+    });
+  }
+
+  function populateContainerSelect(containers) {
+    const select = P.el('term-container-select');
+    select.innerHTML = containers
+      .filter(function (c) { return c.state === 'running'; })
+      .map(function (c) { return '<option value="' + P.escapeHtml(c.id) + '">' + P.escapeHtml(c.name) + '</option>'; })
+      .join('');
+    containerId = select.value || null;
+  }
+
+  function init() {
+    const input = P.el('term-input');
+
+    P.el('term-container-select').addEventListener('change', function (e) {
+      containerId = e.target.value;
+      cwd = '/';
+      P.el('term-output').innerHTML = '';
+    });
+
+    input.addEventListener('keydown', function (e) {
+      if (e.key !== 'Enter') return;
+      const cmd = input.value;
+      input.value = '';
+      if (!containerId) {
+        appendLine('<span style="color:#ef6470;">No running container selected.</span>');
+        return;
+      }
+      if (cmd.trim() === '') return;
+      runCommand(cmd);
+    });
+
+    return P.get('containers', 'list').then(populateContainerSelect).catch(function (err) {
+      appendLine('<span style="color:#ef6470;">' + P.escapeHtml(err.message) + '</span>');
+    });
+  }
+
+  P.registerPanel('terminal', { init: init });
+})();