style: apply black and isort formatting across entire codebase

- Standardize quote style (single to double quotes)
- Reorder and group imports alphabetically
- Fix line breaks and indentation for consistency
- Apply PEP 8 formatting standards

Also updated Makefile to exclude both venv and .venv from code quality checks.

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

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

app/utils/data_processing.py

@@ -109,7 +109,9 @@ class PriceProcessor:
         r"([A-Z]{3})\s*([0-9.,]+)": lambda m: (m.group(2), m.group(1)),
     }
 
-    def parse_price_currency(self, price_str: any) -> Tuple[Optional[str], Optional[str]]:
+    def parse_price_currency(
+        self, price_str: any
+    ) -> Tuple[Optional[str], Optional[str]]:
         """
         Parse a price string to extract the numeric value and currency.