Add structured headers to the PHP include layer, fix monitor state paths

All 16 include/ files now carry PURPOSE / DESIGN PRINCIPLES / OPERATIONAL
SAFEGUARDS / EXPORTS / CONFIGURATION, keeping the first three section names
identical to the bash headers so retrieval can route across both languages.

monitor.php read six watchdog state files from /tmp while the watchdogs write
to STATE_DIR, so every strike set came back empty and the summary reported
healthy unconditionally. docs.php gained path containment before it is wired
to a page.

Plugin/unraid/include/fallback.php

@@ -1,5 +1,52 @@
 <?php
-// Fallback tab data helpers
+// ═══════════════════════════════════════════════════════════════════════════════════════════════
+// PURPOSE
+//   Fallback page data layer. Reports what state each node is in (NORMAL / FALLBACK /
+//   NO_INTERNET / DARK), which tiers have activated, and which covered containers are
+//   actually running — for this host and for every partner.
+//
+// DESIGN PRINCIPLES
+//   Observes fallback.sh; never participates in it.
+//       State is read from the state file the running fallback process maintains. This file
+//       has no opinion about whether a failover should happen and cannot trigger, advance,
+//       or hand back one. The page is a window, not a lever.
+//
+//   Remote state is read the same way local state is.
+//       vv_fb_remote_state() SSHes over and reads the partner's own fallback_state.db rather
+//       than inferring the partner's state from what this host can see. A node's state is
+//       whatever that node believes, not what its neighbour guesses.
+//
+//   Coverage lists come from conf, tier membership from FALLBACK_<HOST>_TIER<n>.
+//       Named for the host being covered, not the host doing the covering — see the fallback
+//       section of the top-level README for why that reads backwards at first.
+//
+// OPERATIONAL SAFEGUARDS
+//   A missing state file parses as empty, not as NORMAL.
+//       vv_fb_local_state() hands an empty string to the parser when the file is absent, so
+//       the page shows unknown rather than asserting everything is fine. Reporting a healthy
+//       state for a fallback process that is not running would be the worst possible lie on
+//       this page.
+//
+//   An unreachable partner degrades to what is locally known.
+//       Remote SSH failures return empty rather than propagating an error, so one dark node
+//       cannot blank the whole page — which is precisely the situation this page exists for.
+//
+//   Read-only over SSH.
+//       The only remote commands issued are a state-file read and `docker ps`. Nothing here
+//       starts or stops a container on either side.
+//
+// EXPORTS
+//   State       vv_fb_local_state(), vv_fb_remote_state(), vv_fb_parse_state()
+//   Containers  vv_fb_local_running(), vv_fb_remote_running(), vv_fb_covers()
+//   Assembly    vv_fb_known_hosts(), vv_fb_all()
+//   Parsing     vv_fb_bash_array(), vv_fb_scalar()
+//
+// CONFIGURATION
+//   STATE_DIR                    fallback_state.db — written by Fallback/fallback.sh
+//   FALLBACK_<HOST>_TIER1..4     containers covered per tier, keyed by the covered host
+//   HOST*_SSH_KEY                used to read partner state
+// ═══════════════════════════════════════════════════════════════════════════════════════════════
+
 
 require_once __DIR__ . '/config.php';
 require_once __DIR__ . '/partnership.php';   // vv_pt_ssh(), vv_pt_ts_peers()