add durable Unity test run state machine

[niqibiao]

Summary

• add Editor-only tests/run and tests/status commands for bounded asynchronous Edit Mode and Play Mode test runs
• require tests/run to use a protected direct invocation and reject it before dispatch when placed in /batch
• derive the public runId from the protected invocation UUID, keep the Test Framework GUID private, and persist current plus 16 historical terminal states
• survive Unity domain reloads with fail-closed ownership checks, bounded state/response sizes, dirty-scene preflight, compact counts, and bounded failure evidence
• advertise test_runs_v1 from the Editor health response and document protected command extension policies for the unity-cli-plugin team and package extenders
• keep public compatibility wording at Unity 2022

Why

Complex agent workflows need to start a Unity Test run once, tolerate Play Mode or assembly reloads, and keep polling the same durable identity without either repeating TestRunnerApi.Execute() or returning a later run's result.

Validation

• Unity 2022 live validation: Edit Mode pass/fail/skip, fixture setup failure, no-match, Play Mode reload completion, 10-second long poll, concurrent-run rejection, historical lookup, dirty-scene preflight, and uppercase historical runId
• exact same protected invocation replay returned replayed=true with the same runId; only one 15.05-second Play Mode run was recorded
• package core Python suite: 35/35
• REPL Python suite: 208/208
• public Markdown wording audit: Unity 2022 only
• Unity refresh/compile completed successfully
• git diff --check

Stack

• base: codex/console-get (PR Add bounded Editor log diagnostics #7)
• companion contracts: unity-cli PR #15