style: apply ruff format to all source and test files

Fixes ruff format --check CI failure. 22 files reformatted to satisfy
the ruff formatter's style requirements. No logic changes, only
whitespace/formatting adjustments.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/skill_seekers/cli/pdf_scraper.py

@@ -712,7 +712,9 @@ def main():
             print("=" * 80)
             if workflow_executed:
                 print(f"   Running after workflow: {workflow_name}")
-                print("   (Workflow provides specialized analysis, enhancement provides general improvements)")
+                print(
+                    "   (Workflow provides specialized analysis, enhancement provides general improvements)"
+                )
             print("   (Use --enhance-workflow for more control)")
             print("")
             # Note: PDF scraper uses enhance_level instead of enhance/enhance_local