refactor: modernize code quality tooling with Ruff

- Replace black, isort, and flake8 with Ruff (all-in-one linter and formatter)
- Add comprehensive pyproject.toml configuration
- Simplify Makefile code quality targets
- Configure exclusions for venv/.venv in pyproject.toml
- Auto-fix 1,359 linting issues across codebase

Benefits:
- Much faster builds (Ruff is written in Rust)
- Single tool replaces multiple tools
- More comprehensive rule set (UP, B, C4, SIM, PIE, RET, Q)
- All configuration centralized in pyproject.toml
- Better import sorting and formatting consistency

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

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

scripts/backup_database.py

@@ -2,12 +2,10 @@
 """Database backup utility that uses project configuration."""
 
 import os
-import shutil
 import sqlite3
 import sys
 from datetime import datetime
 from pathlib import Path
-from urllib.parse import urlparse
 
 # Add project root to Python path
 sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
@@ -25,11 +23,10 @@ def get_database_path():
         if db_path.startswith("./"):
             db_path = db_path[2:]  # Remove ./ prefix
         return db_path
-    else:
-        # For PostgreSQL or other databases, we can't do file backup
-        print(f"[INFO] Database type: {db_url.split('://')[0]}")
-        print("[ERROR] File backup only supported for SQLite databases")
-        return None
+    # For PostgreSQL or other databases, we can't do file backup
+    print(f"[INFO] Database type: {db_url.split('://')[0]}")
+    print("[ERROR] File backup only supported for SQLite databases")
+    return None
 
 
 def backup_sqlite_database():
@@ -78,10 +75,9 @@ def backup_database():
 
     if settings.database_url.startswith("sqlite"):
         return backup_sqlite_database()
-    else:
-        print("[INFO] For PostgreSQL databases, use pg_dump:")
-        print(f"pg_dump {settings.database_url} > backup_$(date +%Y%m%d_%H%M%S).sql")
-        return True
+    print("[INFO] For PostgreSQL databases, use pg_dump:")
+    print(f"pg_dump {settings.database_url} > backup_$(date +%Y%m%d_%H%M%S).sql")
+    return True
 
 
 if __name__ == "__main__":