Add bounded parallel E2E runner for local and CI use

[guima-why]

Changes

• Add one local/CI E2E runner with bounded parallelism, per-case hard timeouts, process-tree cleanup, an explicit case allowlist, and Markdown/HTML/JUnit/JSON reports.
• Select deterministic A2A, REPL and Web API contracts plus the A2A execution-control matrix; add four opt-in live scenarios, including two ROS resource creation cases.
• Adapt the REPL pipeline contract to accept either semantic candidate controls or terminal readiness across PTY implementations.

Verification

• 128 targeted offline tests passed; Ruff passed.
• Local full deterministic suite: 25/25 passed with three concurrent cases.
• CI fast suite: 5/5 passed. CI full suite: 25/25 passed in 71 seconds of test wall time; the test report and artifact upload succeeded.
• Live cloud suite is prepared but awaits test-only credentials.

Notes

• a2a-recovery-contract is excluded after reproducible failure in isolation: its expected persisted aliyun_api result is missing.
• Real cloud cases enforce a 45-minute hard timeout and allow up to 15 minutes for cleanup before killing the process group. Check cleanup status for any forced termination.