chore(phase-4): QA fixes + gitignore portal build artifacts

- Fix 7 test fixtures missing isPublic field added in WS4 Marketplace
- Add portal/.next/ to .gitignore (build artifacts should not be tracked)
- Mark all Phase 4 tasks 11.1-11.11 complete in tasks.md

QA results: 611/611 tests pass, tsc zero errors, portal build OK, CLI build OK

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -5,3 +5,7 @@ coverage/
 .env.*
 *.log
 .DS_Store
+
+# Next.js build output
+portal/.next/
+portal/node_modules/