Main push test failures

Goal

1. Keep test:slowest as a PR-only failure path, not a main push blocker.
2. Fix the failing useEventPlateId behavior or contract so main is green again.

Scope

1. Inspect hook + spec for useEventPlateId.
2. Inspect workflow/scripts that run test:slowest.
3. Add or adjust the smallest regression coverage needed.
4. Implement minimal fixes.
5. Run targeted verification plus required build/type/lint checks for touched code.

Findings

• useEventPlateId already matches the documented contract: explicit id, then focus, blur, last, then provider id.
• The main spec failure was test pollution. EventEditorStore is global, and the spec only reset it in afterEach, so leaked state from earlier tests could beat the provider id on the first assertion.
• main push ran bun check, and check hard-included pnpm test:slowest.
• The right boundary is workflow-level: keep check as the PR gate, and give push CI a separate script that skips only test:slowest.
• Repo-wide lint and both check:push / lint:fix still fail on unrelated .codex/skills/claude-permissions-optimizer/scripts/extract-commands.mjs diagnostics.

Progress

• Loaded relevant skills.
• Read code and relevant docs.
• Reproduce failures locally.
• Fix hook/spec behavior.
• Fix PR-only test:slowest gating.
• Verify.