Add structured headers to the PHP pages layer

Documents each tab's purpose, what it renders, and which endpoints it polls.
Pages that start with markup get the header in a <?php ?> block so it never
reaches the browser.

Also corrects the layer diagram in README-unraid.md: eight of eleven pages hold
no PHP logic and poll api/ for everything — only auth, monitor and scheduler
require an include/ file directly.

Plugin/unraid/pages/docker.php

@@ -1,3 +1,31 @@
+<?php
+// ═══════════════════════════════════════════════════════════════════════════════════════════════
+// PURPOSE
+//   Docker tab. Container inventory grouped into Varaverk-owned folders, with start / stop /
+//   restart controls and WebUI links.
+//
+// DESIGN PRINCIPLES
+//   Pure view — inventory and folder state come from api/docker.php; actions go to
+//   api/docker_action.php. Folder storage and the conf mirror live in include/docker.php.
+//
+//   Folders are Varaverk's own, not folder.view3's. The grouping survives that plugin being
+//   absent or reset; it is synced to only when installed.
+//
+// OPERATIONAL SAFEGUARDS
+//   Destructive actions are confirmed in the browser before the request is sent.
+//
+//   Container actions are routed through a dedicated action endpoint that validates the name
+//   against the real inventory — the page never composes a docker command.
+//
+//   Container names are escaped on render, so a name containing markup cannot inject.
+//
+// RENDERS
+//   Folder-grouped container grid, per-container state, WebUI links, action buttons
+//
+// DEPENDS ON
+//   api/docker.php         polled every 60s   → include/docker.php
+//   api/docker_action.php  start/stop/restart
+?>
 <style>
 .vv-dk-toolbar    { display:flex;align-items:center;gap:8px;margin-bottom:12px;padding:0 2px;flex-wrap:wrap; }
 .vv-dk-title      { font-size:13px;font-weight:bold;color:#888;text-transform:uppercase;letter-spacing:.06em;flex:1; }