feat: Implement Walmart scraper and integrate with existing architecture

- Added Walmart scraper to scrape product data from Walmart.com, including category pages and product details.
- Introduced a stealth browser module to handle bot protection and improve scraping reliability.
- Created a SQLite database for tracking product history, price changes, stock events, and user favorites.
- Developed a Discord bot for user interaction, allowing location setting and stock checking at local stores.
- Implemented a favorites system to manage priority products and categories with custom notification settings.
- Added news aggregation module to fetch and analyze Pokemon TCG news from various sources.
- Created tools for API discovery and monitoring, including a backend monitor for detecting new products.
- Added unit tests for database operations, product filtering, and API endpoints to ensure functionality.
- Enhanced existing modules with improved error handling and logging for better maintainability.

CLAUDE.md

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+# Pokemon Stock Monitor - Project Guide
+
+## Overview
+A Pokemon TCG stock monitoring system that tracks retail sites (Target, PokemonCenter, GameStop, Best Buy, Walmart) for restocks and new drops, sending Discord notifications when products become available.
+
+## Architecture
+
+```
+User -> Chrome Extension (PokemonCenter API interception)
+     -> Python Monitor (main.py) -> Scrapers -> ProductTracker -> Discord Notifications
+     -> Flask Dashboard (localhost:5000) -> REST API
+```
+
+## Directory Structure
+
+### Core Application
+- `main.py` - Entry point, scheduling loop, orchestrates scraping
+- `config.py` - All configuration (intervals, URLs, Discord webhook, browser settings)
+
+### Source Code (`src/`)
+- `browser.py` - Playwright/Chrome browser management
+- `product_tracker.py` - Detects new products and restocks, manages state
+- `discord_notifier.py` - Sends Discord webhook notifications
+- `discord_bot.py` - Interactive Discord bot commands
+- `database.py` - SQLite database for historical tracking
+- `favorites.py` - User favorites/watchlist management
+- `scraper_state.py` - Persists scraper state between runs
+- `store_locator.py` - Target store location lookup
+
+### Scrapers (`scrapers/`)
+- `base.py` - `Product` dataclass, `BaseScraper` abstract class
+- `pokemoncenter.py` - PokemonCenter scraper (needs stealth browser)
+- `target.py` - Target.com scraper
+- `gamestop.py` - GameStop.com scraper (light bot protection)
+- `bestbuy.py` - BestBuy.com scraper (moderate bot protection)
+- `walmart.py` - Walmart.com scraper (aggressive bot protection, may need stealth)
+
+### Chrome Extension (`chrome-extension/`)
+- `manifest.json` - Extension config (MV3)
+- `background.js` - Service worker, manages alarms and notifications
+- `content.js` - Injected into PokemonCenter pages
+- `api-interceptor.js` - Intercepts PokemonCenter API responses
+- `popup.html/js` - Extension popup UI
+
+### Dashboard (`dashboard/`)
+- `app.py` - Flask app, routes
+- `api.py` - REST API endpoints (`/api/*`)
+- `templates/index.html` - Main template
+- `static/app.js` - Frontend JavaScript
+
+### Data (`data/`)
+- `products.json` - Tracked products state
+- `scraper_state.json` - Persisted scraper state
+- `known_skus.json` - Known product SKUs
+- `proxies.json` - Proxy configuration
+- `user_locations.json` - User store locations
+
+### Tools (`tools/`)
+Development and debugging utilities:
+- `api_monitor.py`, `backend_monitor.py` - API monitoring
+- `stealth_browser.py` - Anti-detection browser
+- `capture_api_calls.py` - HAR capture for debugging
+
+## Key Classes
+
+### `Product` (scrapers/base.py)
+```python
+@dataclass
+class Product:
+    name: str
+    url: str
+    price: Optional[str]
+    in_stock: bool
+    image_url: Optional[str]
+    site: str
+    product_id: Optional[str]
+```
+
+### `ProductTracker` (src/product_tracker.py)
+- `process_products(products)` -> `(new_products, restocked_products)`
+- `get_stats()` -> dashboard statistics
+
+### `BaseScraper` (scrapers/base.py)
+- `scrape_category_page(url)` -> `List[Product]`
+- `check_product_stock(url)` -> `(in_stock, price)`
+
+## Common Tasks
+
+### Add a new retailer scraper
+1. Create `scrapers/newsite.py` extending `BaseScraper`
+2. Implement `scrape_category_page()` and `check_product_stock()`
+3. Add to `scrapers/__init__.py`
+4. Add config in `config.py` (URLs, enable flag)
+5. Add check function in `main.py`
+
+### Modify Discord notifications
+- Webhook format: `src/discord_notifier.py`
+- Bot commands: `src/discord_bot.py`
+
+### Change check intervals or URLs
+- Edit `config.py`
+
+### Dashboard changes
+- Routes: `dashboard/app.py`
+- API: `dashboard/api.py`
+- Frontend: `dashboard/static/app.js`
+
+### Chrome extension changes
+- Popup UI: `chrome-extension/popup.html`, `popup.js`
+- API interception: `chrome-extension/api-interceptor.js`
+- Background logic: `chrome-extension/background.js`
+
+## Conventions
+- Python 3.13+
+- Logging via `logging` module (configured in main.py)
+- Dataclasses for data structures
+- Flask for web/API
+- Playwright for browser automation
+- SQLite for persistence (`stats.db`)
+
+## Running
+
+```bash
+# Main monitor
+python main.py
+
+# Dashboard only
+python dashboard/app.py
+
+# Discord bot
+python src/discord_bot.py
+```
+
+## Testing
+```bash
+python -m pytest tests/
+```