fix: normalize non-standard GTIN lengths to EAN-13

- Pad non-standard lengths (9-12 digits) to EAN-13 (13 digits)
- EAN-13 is the European/international standard
- Handle .0 suffix from float conversion in import files
- Change warnings to debug-level logging to reduce noise

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

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

app/utils/data_processing.py

@@ -51,24 +51,19 @@ class GTINProcessor:
         length = len(gtin_clean)
 
         if length in self.VALID_LENGTHS:
-            # Standard lengths - pad appropriately
-            if length == 8:
-                return gtin_clean.zfill(8)  # EAN-8
-            if length == 12:
-                return gtin_clean.zfill(12)  # UPC-A
-            if length == 13:
-                return gtin_clean.zfill(13)  # EAN-13
-            if length == 14:
-                return gtin_clean.zfill(14)  # GTIN-14
+            # Standard lengths - return as-is (already valid)
+            return gtin_clean
 
         elif length > 14:
             # Too long - truncate to EAN-13
-            logger.warning(f"GTIN too long, truncating: {gtin_clean}")
+            logger.debug(f"GTIN too long ({length} digits), truncating: {gtin_clean}")
             return gtin_clean[-13:]
 
-        elif 0 < length < 8:
-            # Too short - pad to EAN-13
-            logger.warning(f"GTIN too short, padding: {gtin_clean}")
+        elif 0 < length < 14:
+            # Non-standard length - pad to EAN-13 (European standard)
+            # EAN-13 is the international standard used in Europe and most of the world
+            # UPC-A (12 digits) is primarily US/Canada
+            logger.debug(f"GTIN non-standard ({length} digits), padding to EAN-13: {gtin_clean}")
             return gtin_clean.zfill(13)
 
         logger.warning(f"Invalid GTIN format: '{gtin_value}'")