feat: migrate website-creator from Next.js+Payload to Astro+Tina CMS

Major changes:
- Replace Payload CMS with Tina CMS (self-hosted)
- Add Astro DB for consent logging (PDPA compliant)
- Update Tailwind v3 to v4 (@tailwindcss/vite plugin)
- Add astro-tina-starter template
- Rewrite consent template for Astro (ConsentBanner.astro, Astro DB, Nano Stores)
- Add install-tina-backend.sh for self-hosted Tina per customer
- Rename convert-astro.sh to migrate-tina.sh
- Add AGENTS.md template for generated websites
- Delete all Payload/Next.js files

Technical updates:
- Astro DB using defineDb with eq operators for queries
- Tailwind v4 with @theme block
- Tina CMS local development mode
- Proper Astro API routes for consent

Research-verified with official documentation (April 2026)

skills/seo-multi-channel/SKILL.md

@@ -142,7 +142,7 @@ Output:
   - meta_description: 150-160 chars
   - slug: Auto-generated (Thai-friendly)
   - images: Saved to website repo
-  - astro_ready: true (content collections format)
+  - payload_cms_ready: true (REST API format)
 ```
 
 **X/Twitter Thread:**
@@ -415,55 +415,55 @@ def save_image_for_channel(image_data: bytes, topic: str, channel: str) -> str:
 ### **Website-Creator Integration:**
 
 ```python
-def publish_blog_to_astro(article_md: str, website_repo: str) -> Dict:
+def publish_blog_to_payload(
+    article_md: str,
+    website_url: str,
+    payload_token: str
+) -> Dict:
     """
-    Publish blog post to Astro content collections
-    Returns deployment status
+    Publish blog post to Payload CMS via REST API
+    Returns publication status
     """
     # Parse frontmatter
     frontmatter = parse_frontmatter(article_md)
-    
+
     # Detect language
     lang = detect_content_language(article_md)
-    
+
     # Generate slug
     slug = generate_slug(frontmatter['title'], lang)
-    
-    # Determine output path
-    output_path = os.path.join(
-        website_repo,
-        'src/content/blog',
-        f'({lang})',
-        f'{slug}.md'
+    if lang == 'th':
+        slug = f'th/{slug}'
+
+    # Convert markdown to Lexical JSON
+    content = markdown_to_lexical(article_md)
+
+    # Prepare Payload document
+    payload_doc = {
+        'title': frontmatter['title'],
+        'slug': slug,
+        'content': content,
+        'status': 'draft',
+        'description': frontmatter.get('description', ''),
+    }
+
+    # Send to Payload CMS API
+    response = requests.post(
+        f'{website_url}/api/posts',
+        headers={'Authorization': f'Bearer {payload_token}'},
+        json=payload_doc
     )
-    
-    # Ensure directory exists
-    os.makedirs(os.path.dirname(output_path), exist_ok=True)
-    
-    # Write article
-    with open(output_path, 'w', encoding='utf-8') as f:
-        f.write(article_md)
-    
-    # Copy images if any
-    if 'images' in frontmatter:
-        for img in frontmatter['images']:
-            # Copy from temp location to website repo
-            dest_path = os.path.join(website_repo, 'public', img['src'].lstrip('/'))
-            os.makedirs(os.path.dirname(dest_path), exist_ok=True)
-            shutil.copy(img['local_path'], dest_path)
-    
-    # Git commit and push
-    subprocess.run(['git', 'add', '.'], cwd=website_repo, check=True)
-    subprocess.run(['git', 'commit', '-m', f'Add blog post: {slug}'], cwd=website_repo, check=True)
-    subprocess.run(['git', 'push', 'origin', 'main'], cwd=website_repo, check=True)
-    
-    # Return deployment info
+
+    result = response.json()
+
+    # Return publication info
     return {
         'published': True,
+        'id': result.get('id'),
         'slug': slug,
         'language': lang,
-        'path': output_path,
-        'deployment_url': f"https://your-domain.com/blog/{slug}" if lang == 'en' else f"https://your-domain.com/th/{slug}"
+        'admin_url': f'{website_url}/admin/collections/posts/{result.get("id")}',
+        'api_url': f'{website_url}/api/posts',
     }
 ```