feat(newos4): maintenance agent channel — triage engine, two-way replies, cron

- scripts/newos4-triage.py: deterministic collector (records vs occurrences, real vs
  noise vs self-referential, new reports since last run, checker WARN/FAIL). Untrusted
  strings are sanitised and prefixed DATA| before they can reach an agent prompt;
  state + output written under flock with mode 644.
- scripts/newos4-reply.py: appends one reply to data/maintenance/replies.json under
  flock. Hermes writes here instead of POSTing with an admin cookie, so an expired
  session can never look like a delivered reply.
- api/debug/agent-replies.php: GET/POST (admin-gated by nginx) half of the thread.
- api/debug/report.php: accepts thread + kind=maintenance so in-app feedback is
  distinguishable from operator bug reports.
- terminal: `feedback <message>` and `feedback-inbox` commands; help.html rows added
  (help coverage 357/357, modules-index regenerated).

Live proof: `feedback "…"` filed RPT-20261023-123825-781fba86 with thread
thr-glmfwae2 and kind=maintenance; agent-replies GET returned the posted reply, POST
returned 201; triage first run reported 9 new reports, second run 0.
Cron: newos4-maintenance (7e3b326daa4c) daily 07:15, newos4-skills-weekly
(cb6bc2a16216) Mondays 06:30.

2 files changed, 66 insertions, 0 deletions

diff --git a/api/debug/agent-replies.php b/api/debug/agent-replies.php
new file mode 100644
index 0000000..070c0e6
--- /dev/null
+++ b/api/debug/agent-replies.php
@@ -0,0 +1,57 @@
+<?php
+// api/debug/agent-replies.php — outbound half of the maintenance thread.
+// Hermes (or the operator) writes replies here; the in-page agent reads them with
+// `feedback-inbox`. nginx gates this path behind the WebX11 admin session, so it is
+// owner-only: never expose it in the public debug/course location block.
+require_once __DIR__ . '/config.php';
+
+define('REPLIES_DIR', __DIR__ . '/../../data/maintenance');
+define('REPLIES_FILE', REPLIES_DIR . '/replies.json');
+
+if (!is_dir(REPLIES_DIR)) {
+    @mkdir(REPLIES_DIR, 0775, true);
+    @chgrp(REPLIES_DIR, 'www-data');
+}
+
+$method = $_SERVER['REQUEST_METHOD'];
+
+if ($method === 'GET') {
+    $since = $_GET['since'] ?? null;
+    $all = load_json(REPLIES_FILE);
+    if (!is_array($all)) $all = [];
+    if ($since) {
+        $all = array_values(array_filter($all, fn($r) => ($r['created_at'] ?? '') > $since));
+    }
+    json_response(['success' => true, 'replies' => array_slice($all, -100)]);
+}
+
+if ($method !== 'POST') {
+    error_response('Method not allowed', 405);
+}
+
+$raw = file_get_contents('php://input');
+if (!$raw) error_response('Empty request body');
+if (strlen($raw) > 16384) error_response('Payload too large (max 16KB)', 413);
+
+$p = json_decode($raw, true);
+if (!is_array($p)) error_response('Invalid JSON');
+
+$body = trim((string)($p['body'] ?? ''));
+if ($body === '') error_response('body is required');
+if (mb_strlen($body) > 2000) $body = mb_substr($body, 0, 2000);
+
+$list = load_json(REPLIES_FILE);
+if (!is_array($list)) $list = [];
+
+$author = (($p['author'] ?? 'hermes') === 'newos4') ? 'newos4' : 'hermes';
+$entry = [
+    'id' => 'REP-' . gmdate('Ymd-His') . '-' . substr(bin2hex(random_bytes(3)), 0, 6),
+    'created_at' => gmdate('c'),
+    'author' => $author,
+    'body' => $body,
+];
+
+$list[] = $entry;
+save_json(REPLIES_FILE, array_slice($list, -200));
+
+json_response(['success' => true, 'id' => $entry['id']], 201);
diff --git a/api/debug/report.php b/api/debug/report.php
index cefcae6..5d4fc95 100644
--- a/api/debug/report.php
+++ b/api/debug/report.php
@@ -29,6 +29,13 @@ $body = (string)($payload['body'] ?? '');
 if (mb_strlen($body) > 4000) $body = mb_substr($body, 0, 4000);
 $diag = (isset($payload['diagnostics']) && is_array($payload['diagnostics'])) ? $payload['diagnostics'] : [];
 
+// Maintenance thread: lets the in-app agent and the Hermes maintenance job hold a conversation.
+// `thread` is a client-generated id (thr-xxxxxxxx); `kind` distinguishes agent feedback from
+// operator bug reports so triage can weight them differently.
+$thread = preg_replace('/[^a-zA-Z0-9_-]/', '', (string)($payload['thread'] ?? ''));
+if (mb_strlen($thread) > 40) $thread = substr($thread, 0, 40);
+$kind = (($payload['kind'] ?? '') === 'maintenance') ? 'maintenance' : 'user';
+
 // Storage guard: data/ is not writable by php-fpm, so never pretend we wrote a report.
 if (!is_dir(REPORTS_DIR)) @mkdir(REPORTS_DIR, 0775, true);
 if (!is_dir(REPORTS_DIR) || !is_writable(REPORTS_DIR)) {
@@ -85,6 +92,8 @@ $record = [
     'title' => $title,
     'body' => $body,
     'diagnostics' => $diag,
+    'thread' => $thread,
+    'kind' => $kind,
     'meta' => [
         'ip' => $ip,
         'ua' => $_SERVER['HTTP_USER_AGENT'] ?? '',