fix: Fix AttributeError in codebase_scraper for build_api_reference

The code was still referencing `args.build_api_reference` which was
changed to `args.skip_api_reference` in v2.5.2 (opt-in to opt-out flags).

This caused the codebase analysis to fail at the end with:
  AttributeError: 'Namespace' object has no attribute 'build_api_reference'

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

src/skill_seekers/cli/codebase_scraper.py

@@ -1190,7 +1190,7 @@ Examples:
         print(f"{'='*60}")
         print(f"Files analyzed: {len(results['files'])}")
         print(f"Output directory: {args.output}")
-        if args.build_api_reference:
+        if not args.skip_api_reference:
             print(f"API reference: {Path(args.output) / 'api_reference'}")
         print(f"{'='*60}\n")