fix: remove dead code, update stale versions, tag-based release workflow

Dead code removed:
- Module.php: remove addIPv4() method (no endpoint, feature removed per CLAUDE.md)
- Curl.php: remove useCookies(), setLog() (security risk — wrote tokens to
  web-accessible CURL.log), head(), getHeadersData() — all unused
- module.css: remove .vf-button, .vf-button-small (never referenced in DOM)
- module.css: remove vestigial #vf-data-server-traffic-sep rule
- module.css: merge duplicate #vf-server-info-error declarations
- publish-release.yml: remove dead version.json generation step (nothing reads it)

Fixes:
- AdminHTML.php: update stale cache version strings 20260207 → 20260319
- hooks.php: update stale keygen.js version string
- hooks.php: remove unused `use WHMCS\User\User` import
- ConfigureService.php: remove unused `use JsonException` import
- module.css: fix .vf-os-details class selector → #vf-os-details ID selector
- client.php + admin.php: reuse existing $vf instead of new Module()
- Module.php: use Cache::forget() instead of forgetPattern() for known key
  (forgetPattern is a no-op on filesystem cache fallback)

Workflow:
- Rewrite publish-release.yml: tag-based triggers only (no automatic releases)
- Triggers on push of v* tags, creates GitHub release with auto-generated notes
- Uses softprops/action-gh-release@v2 — compatible with both Gitea and GitHub

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

modules/servers/VirtFusionDirect/hooks.php

@@ -2,7 +2,6 @@
 
 use WHMCS\Module\Server\VirtFusionDirect\ConfigureService;
 use WHMCS\Module\Server\VirtFusionDirect\Database;
-use WHMCS\User\User;
 
 if (!defined("WHMCS")) {
     die("This file cannot be accessed directly");
@@ -131,7 +130,7 @@ add_hook('ClientAreaFooterOutput', 1, function ($vars) {
 
         return "
     <link href=\"" . htmlspecialchars($systemUrl, ENT_QUOTES, 'UTF-8') . "modules/servers/VirtFusionDirect/templates/css/module.css?v=20260319\" rel=\"stylesheet\">
-    <script src=\"" . htmlspecialchars($systemUrl, ENT_QUOTES, 'UTF-8') . "modules/servers/VirtFusionDirect/templates/js/keygen.js?v=20260207\"></script>
+    <script src=\"" . htmlspecialchars($systemUrl, ENT_QUOTES, 'UTF-8') . "modules/servers/VirtFusionDirect/templates/js/keygen.js?v=20260319\"></script>
     <script>
     document.addEventListener('DOMContentLoaded', function() {
         var osGalleryData = " . json_encode($galleryData, JSON_THROW_ON_ERROR | JSON_HEX_TAG | JSON_HEX_AMP | JSON_HEX_APOS | JSON_HEX_QUOT) . ";