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>

tests/unit/middleware/test_rate_limiter.py

@@ -12,8 +12,7 @@ Tests cover:
 """
 
 from collections import deque
-from datetime import datetime, timedelta, timezone
-from unittest.mock import Mock, patch
+from datetime import UTC, datetime, timedelta
 
 import pytest
 
@@ -53,7 +52,7 @@ class TestRateLimiterBasic:
         # Make 10 requests (at the limit)
         for i in range(max_requests):
             result = limiter.allow_request(client_id, max_requests, 3600)
-            assert result is True, f"Request {i+1} should be allowed"
+            assert result is True, f"Request {i + 1} should be allowed"
 
         assert len(limiter.clients[client_id]) == max_requests
 
@@ -109,7 +108,7 @@ class TestRateLimiterSlidingWindow:
         window_seconds = 10
 
         # Manually add old requests
-        old_time = datetime.now(timezone.utc) - timedelta(seconds=15)
+        old_time = datetime.now(UTC) - timedelta(seconds=15)
         limiter.clients[client_id].append(old_time)
         limiter.clients[client_id].append(old_time)
 
@@ -127,7 +126,7 @@ class TestRateLimiterSlidingWindow:
         window_seconds = 60
 
         # Add recent requests
-        recent_time = datetime.now(timezone.utc) - timedelta(seconds=30)
+        recent_time = datetime.now(UTC) - timedelta(seconds=30)
         limiter.clients[client_id].append(recent_time)
         limiter.clients[client_id].append(recent_time)
 
@@ -147,12 +146,12 @@ class TestRateLimiterSlidingWindow:
         window_seconds = 30
 
         # Add old requests (outside window)
-        old_time = datetime.now(timezone.utc) - timedelta(seconds=60)
+        old_time = datetime.now(UTC) - timedelta(seconds=60)
         limiter.clients[client_id].append(old_time)
         limiter.clients[client_id].append(old_time)
 
         # Add recent request (within window)
-        recent_time = datetime.now(timezone.utc) - timedelta(seconds=10)
+        recent_time = datetime.now(UTC) - timedelta(seconds=10)
         limiter.clients[client_id].append(recent_time)
 
         # Old requests removed, only 1 recent request, so 2 more allowed
@@ -170,7 +169,7 @@ class TestRateLimiterSlidingWindow:
         window_seconds = 1  # 1 second window
 
         # Add old request
-        old_time = datetime.now(timezone.utc) - timedelta(seconds=2)
+        old_time = datetime.now(UTC) - timedelta(seconds=2)
         limiter.clients[client_id].append(old_time)
 
         # Should allow request because old one is outside 1-second window
@@ -188,12 +187,12 @@ class TestRateLimiterCleanup:
         limiter = RateLimiter()
 
         # Add clients with old requests
-        old_time = datetime.now(timezone.utc) - timedelta(hours=25)
+        old_time = datetime.now(UTC) - timedelta(hours=25)
         limiter.clients["old_client_1"].append(old_time)
         limiter.clients["old_client_2"].append(old_time)
 
         # Add client with recent requests
-        recent_time = datetime.now(timezone.utc) - timedelta(hours=1)
+        recent_time = datetime.now(UTC) - timedelta(hours=1)
         limiter.clients["recent_client"].append(recent_time)
 
         # Run cleanup
@@ -215,7 +214,7 @@ class TestRateLimiterCleanup:
         limiter.clients["empty_client_2"] = deque()
 
         # Add client with requests
-        limiter.clients["active_client"].append(datetime.now(timezone.utc))
+        limiter.clients["active_client"].append(datetime.now(UTC))
 
         # Run cleanup
         limiter._cleanup_old_entries()
@@ -233,12 +232,12 @@ class TestRateLimiterCleanup:
         client_id = "mixed_client"
 
         # Add old requests
-        old_time = datetime.now(timezone.utc) - timedelta(hours=30)
+        old_time = datetime.now(UTC) - timedelta(hours=30)
         limiter.clients[client_id].append(old_time)
         limiter.clients[client_id].append(old_time)
 
         # Add recent requests
-        recent_time = datetime.now(timezone.utc) - timedelta(hours=1)
+        recent_time = datetime.now(UTC) - timedelta(hours=1)
         limiter.clients[client_id].append(recent_time)
         limiter.clients[client_id].append(recent_time)
 
@@ -255,10 +254,10 @@ class TestRateLimiterCleanup:
         limiter.cleanup_interval = 0  # Force immediate cleanup
 
         # Set last_cleanup to past
-        limiter.last_cleanup = datetime.now(timezone.utc) - timedelta(hours=2)
+        limiter.last_cleanup = datetime.now(UTC) - timedelta(hours=2)
 
         # Add old client
-        old_time = datetime.now(timezone.utc) - timedelta(hours=25)
+        old_time = datetime.now(UTC) - timedelta(hours=25)
         limiter.clients["old_client"].append(old_time)
 
         # Make request (should trigger cleanup)
@@ -272,7 +271,7 @@ class TestRateLimiterCleanup:
         limiter = RateLimiter()
 
         # Add multiple active clients
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         for i in range(5):
             limiter.clients[f"client_{i}"].append(now - timedelta(hours=i))
 
@@ -305,7 +304,7 @@ class TestRateLimiterStatistics:
         client_id = "active_client"
 
         # Add requests at different times
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         limiter.clients[client_id].append(now - timedelta(minutes=30))  # Within hour
         limiter.clients[client_id].append(now - timedelta(hours=2))  # Within day
         limiter.clients[client_id].append(now - timedelta(hours=12))  # Within day
@@ -322,7 +321,7 @@ class TestRateLimiterStatistics:
         client_id = "old_requests_client"
 
         # Add very old requests
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
         limiter.clients[client_id].append(now - timedelta(days=2))
         limiter.clients[client_id].append(now - timedelta(days=3))
 
@@ -347,7 +346,7 @@ class TestRateLimiterStatistics:
         limiter = RateLimiter()
         client_id = "boundary_client"
 
-        now = datetime.now(timezone.utc)
+        now = datetime.now(UTC)
 
         # Exactly 1 hour ago (should be included)
         limiter.clients[client_id].append(now - timedelta(hours=1, seconds=1))
@@ -485,7 +484,7 @@ class TestRateLimiterEdgeCases:
         limiter = RateLimiter()
 
         # Set last_cleanup to past to ensure cleanup triggers
-        old_cleanup_time = datetime.now(timezone.utc) - timedelta(hours=2)
+        old_cleanup_time = datetime.now(UTC) - timedelta(hours=2)
         limiter.last_cleanup = old_cleanup_time
         limiter.cleanup_interval = 0  # Force cleanup on next request
 
@@ -523,7 +522,7 @@ class TestRateLimiterMemoryManagement:
         client_id = "efficiency_test"
 
         # Add many old requests
-        old_time = datetime.now(timezone.utc) - timedelta(hours=2)
+        old_time = datetime.now(UTC) - timedelta(hours=2)
         for _ in range(1000):
             limiter.clients[client_id].append(old_time)