Major updates: LinkedIn auto-posting, timezone fixes, and Docker improvements

Features:
- Add LinkedIn OAuth integration and auto-posting functionality
- Add scheduler service for automated post publishing
- Add metadata field to generated_posts for LinkedIn URLs
- Add privacy policy page for LinkedIn API compliance
- Add company management features and employee accounts
- Add license key system for company registrations

Fixes:
- Fix timezone issues (use UTC consistently across app)
- Fix datetime serialization errors in database operations
- Fix scheduling timezone conversion (local time to UTC)
- Fix import errors (get_database -> db)

Infrastructure:
- Update Docker setup to use port 8001 (avoid conflicts)
- Add SSL support with nginx-proxy and Let's Encrypt
- Add LinkedIn setup documentation
- Add migration scripts for schema updates

Services:
- Add linkedin_service.py for LinkedIn API integration
- Add scheduler_service.py for background job processing
- Add storage_service.py for Supabase Storage
- Add email_service.py improvements
- Add encryption utilities for token storage

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

config/migrate_add_metadata_to_posts.sql

@@ -0,0 +1,8 @@
+-- Add metadata field to generated_posts table
+-- This field stores additional information like LinkedIn post URLs, auto-posting status, etc.
+
+ALTER TABLE generated_posts
+ADD COLUMN IF NOT EXISTS metadata JSONB DEFAULT '{}'::JSONB;
+
+-- Add comment
+COMMENT ON COLUMN generated_posts.metadata IS 'Additional metadata (LinkedIn post URL, auto-posting status, etc.)';