fix(repo): draw every deciding timeout class in the timeout-fields property

[systemfsoftware-maker]

Layer 1 of the agent-ready failure diagnostics stack (docs/plans/2026-10-01-2306-feat-agent-ready-failure-diagnostics-plan.md, unit U1).

Mutation run 36935602456 failed shard 1/6 in its dry run: the in-source property mse_MutantStatusAndEvidence_PersistedTimeoutFieldsFollowTheReproductionRule drew too few inputs to tell the timeout-fields subject apart from a constant, so the fork refused it as vacuous under the mutation-worker budget (30 runs, seed 1). The CI summary then reported this as an "infrastructure failure".

• The property now draws every timeout class that decides the output (wall-clock, hit-limit, evidence-only, kindless) and checks against an independent model.
• TestRunner.HitLimitReasonText accepts only the canonical Hit limit reached (count/limit) shape.
• Also adds the plan document.

Verified: the property passes under seeds 1-20 at the worker budget, and stryker run --dryRunOnly on packages/stryker-js succeeds.

[ryanleecode]

Reviewed by the merge conductor as part of the diagnostics stack. CI green on this head except where noted in the stack summary (macOS timeouts on #151 are flaky: the same code is green on macOS in #155 and #156; the #156 stryker-js mutation shard times out until main records its first full-cost timing, as this PR's description says). Merging into feat/agent-ready-failure-diagnostics with a merge commit.