feat: initial zeropost-engine structure

- AI service with Anthropic claude-sonnet-4-6
- Bull queue for async generation jobs
- Routes: /api/generate, /api/channels, /api/posts
- PostgreSQL schema: users, channels, posts, generation_jobs
- Supports: post, article, topics generation types

.env.example

@@ -0,0 +1,10 @@
+PORT=3030
+ANTHROPIC_API_KEY=your_key_here
+DB_HOST=localhost
+DB_PORT=5432
+DB_NAME=zeropost
+DB_USER=postgres
+DB_PASS=postgres
+REDIS_HOST=localhost
+REDIS_PORT=6379
+INTERNAL_SECRET=change_me_in_prod