fix: Correct datetime import pattern in RepomixService

Changed from module-level import to direct datetime import for
better readability and consistency with project conventions.

Changes:
- Import: `import datetime` → `from datetime import datetime`
- Usage: `datetime.datetime.now()` → `datetime.now()`

This follows Python best practices and improves code clarity
by avoiding redundant module prefix.

Priority: P1 - HIGH (code quality improvement)

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

Author: jeremyeder

src/agentready/services/repomix.py

@@ -1,9 +1,9 @@
 """Repomix integration service for generating AI-friendly repository context."""
 
-import datetime
 import json
 import shutil
 import subprocess
+from datetime import datetime
 from pathlib import Path
 from typing import Dict, List, Optional, Tuple
 
@@ -257,7 +257,7 @@ def check_freshness(self, max_age_days: int = 7) -> Tuple[bool, str]:
 
         # Check most recent file
         newest_file = max(output_files, key=lambda p: p.stat().st_mtime)
-        age_seconds = datetime.datetime.now().timestamp() - newest_file.stat().st_mtime
+        age_seconds = datetime.now().timestamp() - newest_file.stat().st_mtime
         age_days = age_seconds / (24 * 3600)
 
         if age_days > max_age_days: