fix: Convert French price format to English before sending to AI

**Problem:**
AI was misinterpreting French decimal comma as thousands separator:
- "3,99 €" detected as 399.00 EUR (instead of 3.99 EUR)
- "1,99 €" detected as 199.00 EUR (instead of 1.99 EUR)
- Caused by AI reading comma as grouping separator, not decimal point

**Root Cause:**
French format uses comma for decimals: "3,99 €" = three euros ninety-nine cents
English format uses dot for decimals: "3.99 €" = three euros ninety-nine cents

AI models (trained mostly on English) interpret:
- "3,99" → "3" and "99" separate → 399 (three hundred ninety-nine)
- Should be: "3.99" → 3.99 (three point ninety-nine)

**Solution: Pre-Convert Format Before AI Processing**

1. **Normalize ALL Text** (browserless_service.py:380-386)
   ```python
   # Convert French to English in all page text
   content = re.sub(r'(\d+),(\d{2})\s*€', r'\1.\2 €', content)
   # "3,99 €" → "3.99 €"
   # "12,50 €" → "12.50 €"
   # "1 234,56 €" → "1234.56 €" (also removes space thousands separator)
   ```

2. **Normalize Extracted Price** (browserless_service.py:400-410)
   ```python
   # Convert French format in directly extracted price
   normalized_price = re.sub(r'(\d+),(\d{2})', r'\1.\2', extracted_price)
   # "3,99 €" → "3.99 €"
   # Prepends: "PRIX DÉTECTÉ: 3.99 €" (not "3,99 €")
   ```

3. **Updated AI Prompt** (ai_schema.py:135-158)
   - Removed instructions to convert comma→dot (now done automatically)
   - Added: "The price has already been converted to English format for you"
   - Added explicit warnings about common mistakes:
     * "3.99 €" means 3.99 (NOT 399.00, NOT 3990.00)
     * "1.99 €" means 1.99 (NOT 199.00, NOT 1990.00)
   - Clear examples with both CORRECT and INCORRECT values

**Flow:**
```
Page text: "Lutin 3,99 € Ajouter au panier"
  ↓
Normalization: "Lutin 3.99 € Ajouter au panier"
  ↓
Extracted price: "3,99 €" → Normalized: "3.99 €"
  ↓
Sent to AI: "PRIX DÉTECTÉ: 3.99 €\n\nLutin 3.99 € Ajouter au panier"
  ↓
AI sees only English format: "3.99"
  ↓
AI Response: {"price": 3.99}  ✅ CORRECT
```

**Expected Results:**
- Before: "3,99 €" → AI returns 399.00 ❌
- After: "3,99 €" → Normalized to "3.99 €" → AI returns 3.99 ✅

**Regex Details:**
- `(\d+),(\d{2})\s*€` matches French prices: captures digits before comma, 2 digits after
- `\1.\2 €` replaces with: same digits, dot instead of comma, space + euro symbol
- Handles: 0,99 / 3,99 / 12,99 / 89,99 / 1234,99

Fixes issue where AI misread French decimal comma causing 100x price errors.

app/ai_schema.py

@@ -134,26 +134,28 @@ EXTRACTION_PROMPT_TEMPLATE = """Extract product price and stock status from this
 
 **PRICE (IMPORTANT - French format):**
 - **FIRST**: Look for "PRIX DÉTECTÉ:" at the start of text - this is the extracted price
-- French prices use COMMA for decimals: "12,99 €" means 12.99
-- Thousands separator is SPACE or DOT: "1 234,56 €" or "1.234,56 €" means 1234.56
+- **The price has already been converted to English format for you**
+- French original: "3,99 €" → Already shown to you as: "3.99 €"
+- Just extract the number you see (e.g., "3.99" from "PRIX DÉTECTÉ: 3.99 €")
 - Currency symbol is usually € at the end
 - Look for: "PRIX DÉTECTÉ:", price tags, "Prix:", "€", numbers near "Ajouter au panier"
-- Extract as DECIMAL NUMBER (convert comma to dot): 12,99 -> 12.99
+- Extract as DECIMAL NUMBER: If you see "3.99", return 3.99
 - Ignore crossed-out/barré prices (old prices)
 - If multiple prices, take the current/main price (not the original)
 
-**CRITICAL - Read digits carefully:**
-- PAY CLOSE ATTENTION to first digit: "1,99 €" is NOT "9,99 €"
-- Double-check: Is it 1, 7, 8, or 9? These look similar
-- Small prices (< 5€) are common: 0,99 €, 1,49 €, 1,99 €, 2,99 €, 3,99 €, 4,99 €
-- VERIFY the price makes sense for the product type
+**CRITICAL - Common mistakes to avoid:**
+- "3.99 €" means 3.99 (NOT 399.00, NOT 3990.00)
+- "1.99 €" means 1.99 (NOT 199.00, NOT 1990.00)
+- "0.99 €" means 0.99 (NOT 99.00, NOT 990.00)
+- The decimal point separates euros from cents
+- Small prices (< 10€) are very common for everyday items
 
 - Examples of valid prices:
-  * "1,99 €" -> 1.99 (NOT 9.99)
-  * "0,99 €" -> 0.99 (NOT 9.99)
-  * "89,99 €" -> 89.99
-  * "1 234,56 €" -> 1234.56
-  * "PRIX DÉTECTÉ: 89,99 €" -> 89.99
+  * "PRIX DÉTECTÉ: 1.99 €" -> 1.99 (NOT 199 or 1990)
+  * "PRIX DÉTECTÉ: 3.99 €" -> 3.99 (NOT 399 or 3990)
+  * "0.99 €" -> 0.99 (NOT 99)
+  * "89.99 €" -> 89.99 (NOT 8999)
+  * "1234.56 €" -> 1234.56
 - If you find ANY price with € symbol, extract it with confidence >= 0.8
 - If digits are unclear or blurry, reduce confidence to 0.5-0.7
 - If unclear: set null and confidence < 0.5

app/services/browserless_service.py

@@ -376,6 +376,15 @@ class BrowserlessService:
                 try:
                     content = await page.inner_text('body')
                     logger.info(f"Extracted {len(content)} chars of visible text from page")
+
+                    # Normalize French prices to English format for AI (3,99 € → 3.99 €)
+                    import re
+                    # Replace comma with dot in price patterns: digits,XX € → digits.XX €
+                    content = re.sub(r'(\d+),(\d{2})\s*€', r'\1.\2 €', content)
+                    # Remove spaces in thousands: 1 234.56 → 1234.56
+                    content = re.sub(r'(\d+)\s(\d{3})', r'\1\2', content)
+                    logger.debug("Normalized French price formats to English")
+
                 except Exception as e:
                     # Fallback to HTML content if inner_text fails
                     logger.warning(f"Failed to extract inner_text, falling back to HTML: {e}")
@@ -397,8 +406,17 @@ class BrowserlessService:
 
                 # Prepend extracted price to content if found
                 if extracted_price:
-                    content = f"PRIX DÉTECTÉ: {extracted_price}\n\n{content}"
-                    logger.info(f"Prepended price to content: {extracted_price}")
+                    # Convert French format to English for AI (3,99 → 3.99)
+                    import re
+                    normalized_price = extracted_price
+                    # Replace comma with dot for decimal separator (French to English)
+                    # Pattern: digits, comma, 2 digits → digits, dot, 2 digits
+                    normalized_price = re.sub(r'(\d+),(\d{2})', r'\1.\2', normalized_price)
+                    # Remove spaces in thousands separators if any (1 234,56 → 1234.56)
+                    normalized_price = normalized_price.replace(' ', '')
+
+                    content = f"PRIX DÉTECTÉ: {normalized_price}\n\n{content}"
+                    logger.info(f"Prepended normalized price to content: {normalized_price} (original: {extracted_price})")
                 else:
                     logger.warning("Could not extract price from DOM, relying on text/image only")
             else: