Update CLAUDE.md with comprehensive authentication documentation

- Added User Authentication section with security features
- Updated Frontend Interface section to note authentication requirement
- Updated Database Schema with users table and new channel/video fields
- Updated Database Layer architecture with User model details
- Updated Dependencies to include Flask-Login and bcrypt
- Documented user data isolation and multi-tenant architecture
- Added first-time setup instructions for registration

Documentation now reflects:
- Complete authentication system
- User-scoped data model
- Enhanced video metadata fields
- Security best practices

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

CLAUDE.md

@@ -112,17 +112,48 @@ python main.py
 flask --app main run
 ```
 
+## User Authentication
+
+The application includes a complete user authentication system using Flask-Login and bcrypt:
+
+**Authentication Pages:**
+- `/register` - User registration with email and password
+- `/login` - User login with "remember me" functionality
+- `/logout` - User logout
+
+**Security Features:**
+- Passwords hashed with bcrypt and salt
+- Session-based authentication via Flask-Login
+- Protected routes with `@login_required` decorator
+- User-specific data isolation (multi-tenant architecture)
+- Secure password requirements (minimum 8 characters)
+- Flash messages for all auth actions
+- Redirect to requested page after login
+
+**First Time Setup:**
+1. Start the application
+2. Navigate to http://localhost:5000/register
+3. Create an account
+4. Login and start subscribing to channels
+
+**User Data Isolation:**
+- Each user can only see their own channels and videos
+- Channels are scoped by user_id
+- All routes filter data by current_user.id
+- Users cannot access other users' content
+
 ## Frontend Interface
 
 The application includes a full-featured web interface built with Jinja2 templates:
 
-**Pages:**
-- `/` - Dashboard showing all videos sorted by date (newest first)
-- `/channels` - Channel management page with refresh functionality
+**Pages:** (all require authentication)
+- `/` - Dashboard showing user's videos sorted by date (newest first)
+- `/channels` - User's channel management page with refresh functionality
 - `/add-channel` - Form to subscribe to new YouTube channels
 - `/watch/<video_id>` - Video player page for watching downloaded videos
 
 **Features:**
+- User registration and login system
 - Video grid with thumbnails and metadata
 - Real-time download status indicators (pending, downloading, completed, failed)
 - Inline video downloads from dashboard
@@ -130,6 +161,7 @@ The application includes a full-featured web interface built with Jinja2 templat
 - Channel subscription and management
 - Refresh individual channels to fetch new videos
 - Responsive design for mobile and desktop
+- User-specific navigation showing username
 
 **API Endpoints:**
 - `/api/feed` - Fetch YouTube channel feed and save to database (GET)
@@ -177,11 +209,21 @@ The codebase follows a clean layered architecture with separation of concerns:
 ### Database Layer
 **`models.py`** - SQLAlchemy ORM models
 - `Base`: Declarative base for all models
+- `User`: User model with Flask-Login integration
+  - Stores username, email, password_hash, created_at
+  - Methods: `set_password()`, `check_password()` for bcrypt password handling
+  - Implements UserMixin for Flask-Login compatibility
 - `DownloadStatus`: Enum for download states (pending, downloading, completed, failed)
-- `Channel`: Stores YouTube channel metadata (channel_id, title, link, last_fetched)
-- `VideoEntry`: Stores individual video entries with foreign key to Channel, plus download tracking fields:
-  - `download_status`, `download_path`, `download_started_at`, `download_completed_at`, `download_error`, `file_size`
-- Relationships: One Channel has many VideoEntry records
+- `Channel`: Stores YouTube channel metadata per user
+  - Fields: user_id, channel_id, title, link, rss_url, last_fetched_at
+  - Unique constraint: (user_id, channel_id) - one user can't subscribe twice
+- `VideoEntry`: Stores individual video entries with full metadata
+  - Fields: video_id, title, video_url, thumbnail_url, description, published_at
+  - Download tracking: download_status, download_path, download_started_at, download_completed_at, download_error, file_size
+  - Unique constraint: (video_id, channel_id) - prevents duplicate videos
+- Relationships:
+  - One User has many Channels
+  - One Channel has many VideoEntries
 
 **`database.py`** - Database configuration and session management
 - `DATABASE_URL`: Database URL from environment variable (PostgreSQL in production, SQLite fallback for local dev)
@@ -315,18 +357,32 @@ source .venv/bin/activate && alembic downgrade -1
 
 ## Database Schema
 
+**users table:**
+- `id`: Primary key
+- `username`: Unique username (indexed)
+- `email`: Unique email address (indexed)
+- `password_hash`: Bcrypt-hashed password
+- `created_at`: Timestamp when user registered
+
 **channels table:**
 - `id`: Primary key
-- `channel_id`: YouTube channel ID (unique, indexed)
+- `user_id`: Foreign key to users.id (indexed)
+- `channel_id`: YouTube channel ID (indexed)
 - `title`: Channel title
 - `link`: Channel URL
-- `last_fetched`: Timestamp of last feed fetch
+- `rss_url`: YouTube RSS feed URL
+- `last_fetched_at`: Timestamp of last feed fetch
+- Unique index: `idx_user_channel` on (user_id, channel_id) - prevents duplicate subscriptions
 
 **video_entries table:**
 - `id`: Primary key
 - `channel_id`: Foreign key to channels.id
+- `video_id`: YouTube video ID (indexed)
 - `title`: Video title
-- `link`: Video URL (unique)
+- `video_url`: YouTube video URL (indexed)
+- `thumbnail_url`: Video thumbnail URL
+- `description`: Video description
+- `published_at`: When video was published on YouTube (indexed)
 - `created_at`: Timestamp when video was first recorded
 - `download_status`: Enum (pending, downloading, completed, failed)
 - `download_path`: Local file path to downloaded MP4
@@ -334,8 +390,10 @@ source .venv/bin/activate && alembic downgrade -1
 - `download_completed_at`: When download finished
 - `download_error`: Error message if download failed
 - `file_size`: Size in bytes of downloaded file
+- Unique index: `idx_video_id_channel` on (video_id, channel_id) - prevents duplicates
 - Index: `idx_channel_created` on (channel_id, created_at) for fast queries
 - Index: `idx_download_status` on download_status for filtering
+- Index: `idx_published_at` on published_at for date sorting
 
 ## Video Download System
 
@@ -386,6 +444,8 @@ All services have health checks and automatic restarts configured.
 ## Dependencies
 
 - **Flask 3.1.2+**: Web framework
+- **Flask-Login 0.6.0+**: User session management
+- **bcrypt 4.0.0+**: Password hashing
 - **feedparser 6.0.12+**: RSS/Atom feed parsing
 - **SQLAlchemy 2.0.0+**: ORM for database operations
 - **psycopg2-binary 2.9.0+**: PostgreSQL database driver