feat: Cast Iron Scout agent prototype

- Created autonomous cast iron deal scanner
- Scans eBay RSS feeds hourly for cast iron cookware
- Calculates FMV based on brand, type, size
- Sends Telegram alerts for deals ≥50% below FMV
- Identifies Griswold, Wagner, Wapak, Birmingham, Lodge, Victor
- Tracks seen items to avoid duplicate alerts
- Valuation engine with size multipliers
- Configurable preferences in config.json

Known issue: eBay RSS unreliable - next iteration will use proper scraping

agents/cast-iron-scout/valuation.py

@@ -0,0 +1,115 @@
+#!/usr/bin/env python3
+"""
+Cast Iron Valuation Engine
+Determines fair market value and calculates discount percentage
+"""
+import re
+
+# Base price ranges for common cast iron items (in good condition)
+BASE_PRICES = {
+    'griswold': {'skillet': 150, 'griddle': 200, 'dutch_oven': 250, 'pot': 120, 'pan': 100},
+    'wagner': {'skillet': 120, 'griddle': 180, 'dutch_oven': 220, 'pot': 100, 'pan': 90},
+    'wapak': {'skillet': 180, 'griddle': 220, 'dutch_oven': 280, 'pot': 150, 'pan': 130},
+    'birmingham': {'skillet': 160, 'griddle': 190, 'dutch_oven': 240, 'pot': 130, 'pan': 110},
+    'lodge': {'skillet': 80, 'griddle': 120, 'dutch_oven': 150, 'pot': 70, 'pan': 60},
+    'victor': {'skillet': 140, 'griddle': 170, 'dutch_oven': 210, 'pot': 120, 'pan': 100},
+    'default': {'skillet': 100, 'griddle': 150, 'dutch_oven': 200, 'pot': 80, 'pan': 70}
+}
+
+# Size multipliers
+SIZE_MULTIPLIERS = {
+    '#1': 0.5, '#2': 0.6, '#3': 0.7, '#4': 0.8, '#5': 0.9,
+    '#6': 1.0, '#7': 1.1, '#8': 1.2, '#9': 1.3, '#10': 1.4,
+    '#11': 1.5, '#12': 1.6, '#13': 1.7, '#14': 1.8
+}
+
+def identify_brand(title):
+    """Identify the brand from title"""
+    title_lower = title.lower()
+    
+    brands = ['griswold', 'wagner', 'wapak', 'birmingham', 'lodge', 'victor', 'hollowware']
+    for brand in brands:
+        if brand in title_lower:
+            return brand
+    
+    return 'default'
+
+def identify_item_type(title):
+    """Identify the type of item from title"""
+    title_lower = title.lower()
+    
+    types = ['skillet', 'griddle', 'dutch oven', 'pot', 'pan', 'grill', 'waffle', 'mold']
+    for item_type in types:
+        if item_type in title_lower:
+            return item_type.replace(' ', '_')
+    
+    return 'skillet'  # Default to skillet
+
+def extract_size(title):
+    """Extract size number from title"""
+    # Look for patterns like #8, 8 inch, size 8, etc.
+    patterns = [
+        r'#(\d{1,2})',
+        r'size\s*(\d{1,2})',
+        r'(\d{1,2})\s*inch',
+        r'(\d{1,2})\s*"',
+    ]
+    
+    for pattern in patterns:
+        match = re.search(pattern, title, re.IGNORECASE)
+        if match:
+            size_num = match.group(1)
+            return f"#{size_num}"
+    
+    return '#8'  # Default to #8
+
+def calculate_fmv(title):
+    """
+    Calculate Fair Market Value for an item
+    Returns estimated FMV based on brand, type, and size
+    """
+    brand = identify_brand(title)
+    item_type = identify_item_type(title)
+    size = extract_size(title)
+    
+    # Get base price
+    brand_prices = BASE_PRICES.get(brand, BASE_PRICES['default'])
+    base_price = brand_prices.get(item_type, brand_prices['skillet'])
+    
+    # Apply size multiplier
+    multiplier = SIZE_MULTIPLIERS.get(size, 1.0)
+    fmv = base_price * multiplier
+    
+    return round(fmv, 2)
+
+def is_good_deal(price, title, min_discount=50):
+    """
+    Determine if an item is a good deal
+    Returns (is_deal, discount_percent, fmv)
+    """
+    fmv = calculate_fmv(title)
+    
+    if price <= 0 or fmv <= 0:
+        return False, 0, fmv
+    
+    discount_percent = ((fmv - price) / fmv) * 100
+    
+    if discount_percent >= min_discount:
+        return True, discount_percent, fmv
+    
+    return False, discount_percent, fmv
+
+if __name__ == "__main__":
+    # Test the valuation engine
+    test_items = [
+        "Griswold #8 Skillet - Rusty",
+        "Wagner Sidney O -AI - Vintage Cast Iron",
+        "Wapak Funny Face Skillet #10",
+        "Birmingham Stove & Range Co. #12 Skillet"
+    ]
+    
+    print("Valuation Engine Test:\n")
+    for title in test_items:
+        fmv = calculate_fmv(title)
+        print(f"{title[:50]}")
+        print(f"  → FMV: ${fmv}\n")