Implement version 0.0.2 features

Add product version management:
- ProductVersion model and VersionManager class
- VersionAdminController with meta box on product edit page
- AJAX-based version CRUD (add, delete, toggle status)
- JavaScript for version management UI

Add email notifications:
- LicenseEmailController for order emails
- License keys included in order completed emails
- Support for both HTML and plain text emails

Add REST API rate limiting:
- 30 requests per minute per IP
- Cloudflare and proxy-aware IP detection
- HTTP 429 response with Retry-After header

Other changes:
- Bump version to 0.0.2
- Update CHANGELOG.md
- Add version status styles to admin.css

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

src/Product/ProductVersion.php

@@ -0,0 +1,137 @@
+<?php
+/**
+ * Product Version Model
+ *
+ * @package Jeremias\WcLicensedProduct\Product
+ */
+
+declare(strict_types=1);
+
+namespace Jeremias\WcLicensedProduct\Product;
+
+/**
+ * Product version entity model
+ */
+class ProductVersion
+{
+    private int $id;
+    private int $productId;
+    private string $version;
+    private int $majorVersion;
+    private int $minorVersion;
+    private int $patchVersion;
+    private ?string $releaseNotes;
+    private ?string $downloadUrl;
+    private bool $isActive;
+    private \DateTimeInterface $releasedAt;
+    private \DateTimeInterface $createdAt;
+
+    /**
+     * Create version from database row
+     */
+    public static function fromArray(array $data): self
+    {
+        $version = new self();
+        $version->id = (int) $data['id'];
+        $version->productId = (int) $data['product_id'];
+        $version->version = $data['version'];
+        $version->majorVersion = (int) $data['major_version'];
+        $version->minorVersion = (int) $data['minor_version'];
+        $version->patchVersion = (int) $data['patch_version'];
+        $version->releaseNotes = $data['release_notes'] ?: null;
+        $version->downloadUrl = $data['download_url'] ?: null;
+        $version->isActive = (bool) $data['is_active'];
+        $version->releasedAt = new \DateTimeImmutable($data['released_at']);
+        $version->createdAt = new \DateTimeImmutable($data['created_at']);
+
+        return $version;
+    }
+
+    /**
+     * Parse version string into components
+     */
+    public static function parseVersion(string $versionString): array
+    {
+        $parts = explode('.', $versionString);
+        return [
+            'major' => (int) ($parts[0] ?? 0),
+            'minor' => (int) ($parts[1] ?? 0),
+            'patch' => (int) ($parts[2] ?? 0),
+        ];
+    }
+
+    public function getId(): int
+    {
+        return $this->id;
+    }
+
+    public function getProductId(): int
+    {
+        return $this->productId;
+    }
+
+    public function getVersion(): string
+    {
+        return $this->version;
+    }
+
+    public function getMajorVersion(): int
+    {
+        return $this->majorVersion;
+    }
+
+    public function getMinorVersion(): int
+    {
+        return $this->minorVersion;
+    }
+
+    public function getPatchVersion(): int
+    {
+        return $this->patchVersion;
+    }
+
+    public function getReleaseNotes(): ?string
+    {
+        return $this->releaseNotes;
+    }
+
+    public function getDownloadUrl(): ?string
+    {
+        return $this->downloadUrl;
+    }
+
+    public function isActive(): bool
+    {
+        return $this->isActive;
+    }
+
+    public function getReleasedAt(): \DateTimeInterface
+    {
+        return $this->releasedAt;
+    }
+
+    public function getCreatedAt(): \DateTimeInterface
+    {
+        return $this->createdAt;
+    }
+
+    /**
+     * Convert to array
+     */
+    public function toArray(): array
+    {
+        return [
+            'id' => $this->id,
+            'product_id' => $this->productId,
+            'version' => $this->version,
+            'major_version' => $this->majorVersion,
+            'minor_version' => $this->minorVersion,
+            'patch_version' => $this->patchVersion,
+            'release_notes' => $this->releaseNotes,
+            'download_url' => $this->downloadUrl,
+            'is_active' => $this->isActive,
+            'released_at' => $this->releasedAt->format('Y-m-d H:i:s'),
+            'created_at' => $this->createdAt->format('Y-m-d H:i:s'),
+        ];
+    }
+}