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>

scripts/backup_database.py

@@ -2,9 +2,9 @@
 """Database backup utility that uses project configuration."""
 
 import os
-import sys
 import shutil
 import sqlite3
+import sys
 from datetime import datetime
 from pathlib import Path
 from urllib.parse import urlparse
@@ -19,10 +19,10 @@ def get_database_path():
     """Extract database path from DATABASE_URL."""
     db_url = settings.database_url
 
-    if db_url.startswith('sqlite:///'):
+    if db_url.startswith("sqlite:///"):
         # Remove sqlite:/// prefix and handle relative paths
-        db_path = db_url.replace('sqlite:///', '')
-        if db_path.startswith('./'):
+        db_path = db_url.replace("sqlite:///", "")
+        if db_path.startswith("./"):
             db_path = db_path[2:]  # Remove ./ prefix
         return db_path
     else:
@@ -76,7 +76,7 @@ def backup_database():
     print("[BACKUP] Starting database backup...")
     print(f"[INFO] Database URL: {settings.database_url}")
 
-    if settings.database_url.startswith('sqlite'):
+    if settings.database_url.startswith("sqlite"):
         return backup_sqlite_database()
     else:
         print("[INFO] For PostgreSQL databases, use pg_dump:")