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>

app/services/code_quality_service.py

@@ -7,16 +7,16 @@ import json
 import logging
 import subprocess
 from datetime import datetime
-from pathlib import Path
-from typing import Dict, List, Optional, Tuple
 
 from sqlalchemy import desc, func
 from sqlalchemy.orm import Session
 
-from app.models.architecture_scan import (ArchitectureRule, ArchitectureScan,
-                                          ArchitectureViolation,
-                                          ViolationAssignment,
-                                          ViolationComment)
+from app.models.architecture_scan import (
+    ArchitectureScan,
+    ArchitectureViolation,
+    ViolationAssignment,
+    ViolationComment,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -118,7 +118,7 @@ class CodeQualityService:
         logger.info(f"Scan completed: {scan.total_violations} violations found")
         return scan
 
-    def get_latest_scan(self, db: Session) -> Optional[ArchitectureScan]:
+    def get_latest_scan(self, db: Session) -> ArchitectureScan | None:
         """Get the most recent scan"""
         return (
             db.query(ArchitectureScan)
@@ -126,11 +126,11 @@ class CodeQualityService:
             .first()
         )
 
-    def get_scan_by_id(self, db: Session, scan_id: int) -> Optional[ArchitectureScan]:
+    def get_scan_by_id(self, db: Session, scan_id: int) -> ArchitectureScan | None:
         """Get scan by ID"""
         return db.query(ArchitectureScan).filter(ArchitectureScan.id == scan_id).first()
 
-    def get_scan_history(self, db: Session, limit: int = 30) -> List[ArchitectureScan]:
+    def get_scan_history(self, db: Session, limit: int = 30) -> list[ArchitectureScan]:
         """
         Get scan history for trend graphs
 
@@ -158,7 +158,7 @@ class CodeQualityService:
         file_path: str = None,
         limit: int = 100,
         offset: int = 0,
-    ) -> Tuple[List[ArchitectureViolation], int]:
+    ) -> tuple[list[ArchitectureViolation], int]:
         """
         Get violations with filtering and pagination
 
@@ -217,7 +217,7 @@ class CodeQualityService:
 
     def get_violation_by_id(
         self, db: Session, violation_id: int
-    ) -> Optional[ArchitectureViolation]:
+    ) -> ArchitectureViolation | None:
         """Get single violation with details"""
         return (
             db.query(ArchitectureViolation)
@@ -348,7 +348,7 @@ class CodeQualityService:
         logger.info(f"Comment added to violation {violation_id} by user {user_id}")
         return comment_obj
 
-    def get_dashboard_stats(self, db: Session) -> Dict:
+    def get_dashboard_stats(self, db: Session) -> dict:
         """
         Get statistics for dashboard
 
@@ -507,7 +507,7 @@ class CodeQualityService:
         score = 100 - (scan.errors * 0.5 + scan.warnings * 0.05)
         return max(0, min(100, int(score)))  # Clamp to 0-100
 
-    def _get_git_commit_hash(self) -> Optional[str]:
+    def _get_git_commit_hash(self) -> str | None:
         """Get current git commit hash"""
         try:
             result = subprocess.run(