chore: clean up repo structure

- Add node_modules/, test-results/, e2e-report/, .omp/ to .gitignore
- Remove throwaway debug scripts (debug-pw*.js, debug-login-dom.js)
- Remove empty mock-server/ directory
- Untrack harness artifact (.omp/plans/)
- Add missing project files to git (e2e tests, Dockerfiles, tooling configs)

.gitignore

@@ -26,3 +26,13 @@ Thumbs.db
 *~
 .vscode/
 .idea/
+
+# Node
+node_modules/
+
+# Test artifacts
+test-results/
+e2e-report/
+
+# Harness
+.omp/