fix(simulation): invalidate obsolete REST compile-to-start ownership

[ttbombadil]

Summary

• Give pending REST compile-to-start work a synchronous generation owner; suppress obsolete success, compiler-error and transport-error callbacks.
• Invalidate on Stop (also offline), newer starts/compiles, workspace replacement, explicit file/example/external code loading and unmount. Cover public mutation entrypoints and start refs.
• Cancel the existing delayed Reset when its start intent is superseded.
• Release only a cancelled pending compile's indicators; preserve the sandbox compilation phase and compiled snapshot payload for accepted results.

Reproduction and scope

Base: freshly fetched 5b425872cc90fc23c617a4792fdc06146db5b417, after green post-merge CI for #189.

Real React Query/controller hooks with deferred HTTP responses reproduced nine main regressions. React Query already prevents obsolete per-call success callbacks and post-unmount starts; shared mutation callbacks still let an old failure stop a newer run. These callbacks now obey the same ownership guard.

Independent review found cancellation could leave compile indicators busy without a WebSocket terminal response. Three additional RED/GREEN cases cover offline cancellation, external replacement and cancellation before the mutation body runs. Standalone Compile supersession has another RED/GREEN test. Focused suites: 67 passed.

Ordinary editor edits and same-project tab navigation retain the captured-source behavior. Context cancellation is explicit at existing replacement/load boundaries and tracks workspace identity, avoiding a new editor or Tutor policy. No HTTP/WebSocket payload or external API contract changes; no SSOT/ADR/Tutor/Planner/Mastery/Prompt changes or Provider calls.

Verification

• Full unit/coverage and Sonar quality gate, types, docs, read-only lint and build.
• Real toolchain integration, Docker integration and complete Chromium E2E.
• Local E2E uses the existing temporary port3307 adapter with unchanged assertions because an unrelated project owns3000.
• Normal commit and pre-push gates; no bypass. Protected/untracked user files untouched.