feat: add PowerDNS reverse DNS (PTR) integration

Introduces an opt-in reverse DNS management subsystem backed by a PowerDNS
Authoritative HTTP API. Runs via a companion WHMCS addon module
(modules/addons/VirtFusionDns) that holds settings and a Test Connection
page; the server module reads those settings from tbladdonmodules and
short-circuits when the addon is absent or disabled, so provisioning is
unaffected for operators who don't use the feature.

Lifecycle hooks:
- createAccount creates PTRs for every assigned IP (forward DNS must
  already resolve to the IP — FCrDNS enforcement)
- renameServer updates only PTRs whose content matched the old hostname,
  preserving client-custom records
- terminateAccount deletes all PTRs before the local state is purged
- TestConnection merges PowerDNS health check with the existing VirtFusion
  check
- A DailyCronJob hook reconciles missing PTRs additive-only (never
  overwrites)

Client UI: new "Reverse DNS" panel on the service overview with one
editable PTR input per assigned IP, per-row status badges, and
forward-DNS rejection on save. Admin services tab gets a parallel
widget with Reconcile (additive) and Reconcile (force reset) buttons.

New subsystem at lib/PowerDns/:
- Client.php    PowerDNS API wrapper (X-API-Key, listZones/getZone/
                patchRRset/notifyZone), auto-NOTIFY on successful PATCH
- Config.php    Loads + decrypts addon settings from tbladdonmodules
- IpUtil.php    PTR-name generation (IPv4 + IPv6), zone matching,
                RFC 2317 classless parsing
- Resolver.php  FCrDNS verification via dns_get_record with CNAME-chain
                following and per-(hostname,ip) caching
- PtrManager.php Orchestrator: syncServer, deleteForServer, listPtrs,
                setPtr, reconcile, reconcileAll

Security hardening helpers added to Module and applied to the rDNS
endpoints:
- requirePost()           HTTP method gate (405 on non-POST mutations)
- requireSameOrigin()     Origin/Referer check against WHMCS host (CSRF
                          defence against cross-site form POST)
- requireServiceStatus()  tblhosting.domainstatus filter (Active for
                          writes, Active+Suspended for reads)

RFC 2317 classless delegations (e.g. 64/64.113.0.203.in-addr.arpa.)
supported with alignment validation: rejects misaligned start addresses
that don't correspond to any real delegation boundary.

PowerDNS zone IDs containing '/' are URL-encoded as '=2F' per the
PowerDNS API convention. PATCH success triggers PUT /zones/{id}/notify
so slaves pick up the SOA-bumped serial immediately.

Includes IPv4 + IPv6 support, per-IP write rate limit (10s), fresh
IP-ownership re-verification on every client write (defends against
stale-ownership after IP reassignment), and audit logging of every
successful edit to the WHMCS module log.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

modules/servers/VirtFusionDirect/hooks.php

@@ -1,14 +1,68 @@
 <?php
 
+/**
+ * WHMCS hooks for the VirtFusion module.
+ *
+ * HOW HOOKS WORK IN WHMCS
+ * -----------------------
+ * add_hook('EventName', $priority, $callback) registers $callback to fire on
+ * the named event. WHMCS discovers hook files by walking modules/servers/*
+ * /hooks.php and modules/addons/* /hooks.php on every page load, then invokes
+ * every registered hook for the current event.
+ *
+ * Hooks run IN-REQUEST — there's no queue or background worker. Anything
+ * expensive in a hook (like an external API call) blocks the user's page
+ * load. For that reason we only do:
+ *   - Fast in-process work (building DOM snippets, validating session state)
+ *   - Scheduled work on DailyCronJob where "in-request" means the cron worker,
+ *     not a user session
+ *
+ * HOOKS REGISTERED HERE
+ * ---------------------
+ *   DailyCronJob                — PowerDNS reconciliation across all services
+ *   ShoppingCartValidateCheckout — blocks checkout until OS is selected
+ *   ClientAreaFooterOutput      — injects the OS/SSH-key gallery on order form
+ *
+ * FAILURE SEMANTICS
+ * -----------------
+ * Every hook wraps its body in try/catch and silently absorbs any exception.
+ * A hook that throws would potentially break the entire WHMCS request for
+ * all users, not just this module — so we log and swallow, preferring
+ * degraded functionality over site-wide breakage.
+ */
+
 use WHMCS\Database\Capsule;
 use WHMCS\Module\Server\VirtFusionDirect\ConfigureService;
 use WHMCS\Module\Server\VirtFusionDirect\Database;
+use WHMCS\Module\Server\VirtFusionDirect\Log;
 use WHMCS\Module\Server\VirtFusionDirect\Module;
+use WHMCS\Module\Server\VirtFusionDirect\PowerDns\Config as PowerDnsConfig;
+use WHMCS\Module\Server\VirtFusionDirect\PowerDns\PtrManager;
 
 if (! defined('WHMCS')) {
     exit('This file cannot be accessed directly');
 }
 
+/**
+ * Daily PowerDNS reconciliation.
+ *
+ * Walks every managed service and creates any missing PTRs (never overwrites existing
+ * values — cron is additive-only). Requires the VirtFusion DNS addon to be activated
+ * and enabled; otherwise short-circuits immediately.
+ *
+ * All error handling lives inside reconcileAll(); this wrapper just logs any escape
+ * without disturbing the rest of the daily cron run.
+ */
+add_hook('DailyCronJob', 1, function ($vars) {
+    try {
+        if (PowerDnsConfig::isEnabled()) {
+            (new PtrManager)->reconcileAll();
+        }
+    } catch (Throwable $e) {
+        Log::insert('PowerDns:DailyCronJob', [], $e->getMessage());
+    }
+});
+
 /**
  * Shopping Cart Validation Hook
  *