test(e2e): retire legacy e2e after validation

[LayZeeDK]

Parent: #319

Title: Retire legacy e2e tests after validation

Summary
Remove outdated legacy e2e test implementation once the new consolidated e2e-suite has passed validation criteria (two consecutive green matrix runs) and update documentation accordingly.

Objectives

• Simplify maintenance by eliminating duplicated correctness flows.
• Reduce CI runtime and noise.

Scope / Tasks

1. Validation Gate
   • Confirm via CI logs two consecutive successful full matrix runs with both suites.
2. Removal
   • Delete legacy e2e spec file(s) and any unused helper scripts specific to legacy.
   • Remove legacy e2e target from project.json.
3. CI Update
   • Adjust workflow to invoke only e2e-suite target.
4. Docs & References
   • Update README and refactoring guides to reference new suite exclusively.
   • Add CHANGELOG entry noting retirement (performance unaffected).
5. Cleanup
   • Remove any temp directory patterns unique to legacy from .gitignore (if present).
   • Ensure Verdaccio scripts still used or consolidated; remove dead code.
6. Close-Out
   • Comment on Issue Adopt new end-to-end test plan #319 summarizing dates of validation runs; link PR.

Acceptance Criteria

• Legacy files & target removed; CI green with only new suite.
• No orphaned references in docs or scripts.
• Issue Adopt new end-to-end test plan #319 updated; this sub-issue closed.

Dependencies

• Successful parallel validation (Issue: Parallel run new suite).

Out of Scope

• Additional scenario additions; performance benchmarking changes.

Definition of Done
PR merged; CI passing; documentation updated; legacy eliminated; issue closed.