Implement version 0.0.3 features

- Add file attachment support for product versions (Media Library)
- Add version auto-detection from uploaded filenames
- Implement secure customer downloads with hash verification
- Add license key copy-to-clipboard functionality
- Redesign customer licenses page with card-based UI
- Fix product versions meta box visibility for non-licensed types
- Add DownloadController for secure file delivery
- Update CLAUDE.md roadmap and session history

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/Product/VersionManager.php

@@ -97,7 +97,8 @@ class VersionManager
         int $productId,
         string $version,
         ?string $releaseNotes = null,
-        ?string $downloadUrl = null
+        ?string $downloadUrl = null,
+        ?int $attachmentId = null
     ): ?ProductVersion {
         global $wpdb;
 
@@ -114,9 +115,10 @@ class VersionManager
                 'patch_version' => $parsed['patch'],
                 'release_notes' => $releaseNotes,
                 'download_url' => $downloadUrl,
+                'attachment_id' => $attachmentId,
                 'is_active' => 1,
             ],
-            ['%d', '%s', '%d', '%d', '%d', '%s', '%s', '%d']
+            ['%d', '%s', '%d', '%d', '%d', '%s', '%s', '%d', '%d']
         );
 
         if ($result === false) {
@@ -133,7 +135,8 @@ class VersionManager
         int $versionId,
         ?string $releaseNotes = null,
         ?string $downloadUrl = null,
-        ?bool $isActive = null
+        ?bool $isActive = null,
+        ?int $attachmentId = null
     ): bool {
         global $wpdb;
 
@@ -155,6 +158,11 @@ class VersionManager
             $formats[] = '%d';
         }
 
+        if ($attachmentId !== null) {
+            $data['attachment_id'] = $attachmentId > 0 ? $attachmentId : null;
+            $formats[] = $attachmentId > 0 ? '%d' : null;
+        }
+
         if (empty($data)) {
             return true;
         }