refactor: consolidate internal documentation exclusions in .npmignore

- Removed redundant comments listing individual internal docs (CHANGELOG.md, PUBLISHING_GUIDE.md, etc.)
- Simplified .npmignore to reference docs/internal/ directory where these files now reside
- Deleted CHANGELOG.md and PACKAGE_VERIFICATION.md from repository root as they've been moved to internal documentation structure

Author: github-actions[bot]

.npmignore

@@ -31,15 +31,7 @@ PR_DESCRIPTION.md
 TECHNICAL_DEBT_CHECKLIST.md
 TEST_STABILIZATION_REPORT*.md
 
-# Internal release documentation (NOT for npm users)
-CHANGELOG.md
-PUBLISHING_GUIDE.md
-RELEASE_CHECKLIST.md
-CONTRIBUTING.md
-CODE_OF_CONDUCT.md
-SECURITY.md
-
-# Internal documentation (now in docs/internal/)
+# Internal documentation (moved to docs/internal/)
 docs/internal/
 docs/VERSIONING.md
 docs/migrations/