refactor(bundle-size): use free-function helpers for timers

[layershifter]

Summary

Introduces single-character-mangleable wrappers in Utils.ts for the window timer APIs whose property names would otherwise be preserved verbatim by the minifier:

• setTimer / clearTimer / isTimerActive, operating on an opaque Timer = { id } handle stored on instance fields.

setTimer(t, window, callback, delay) lazily creates the Timer when passed undefined and returns it, so callers just write this._timer = setTimer(this._timer, …) — no separate constructor-time allocation. Timer.id is typed as ReturnType<typeof setTimeout> so the id round-trips through window.setTimeout / clearTimeout without a cast; undefined is the not-pending sentinel.

All src/**/*.ts call sites converted; raw .setTimeout / .clearTimeout property accesses now eliminated outside Utils.ts.

Enforced via two additional no-restricted-syntax entries in eslint.config.mjs (next to the existing event-helper rules from #560) so the wrappers can't drift back into raw timer calls in future PRs.

Stack context

Follow-up to #560 — same wrapper pattern applied to timer APIs.

[github-actions]

📊 Bundle size report

Package & Exports	Baseline (minified/GZIP)	PR	Change
tabster all exports	110.491 kB 29.988 kB	108.903 kB 29.92 kB	-1.588 kB -68 B
tabster createTabster (core)	38.098 kB 11.41 kB	37.689 kB 11.452 kB	-409 B 42 B
tabster focusable.findAll	38.121 kB 11.418 kB	37.712 kB 11.46 kB	-409 B 42 B
tabster focusable.findLast	38.122 kB 11.418 kB	37.713 kB 11.46 kB	-409 B 42 B
tabster focusable.findNext	38.122 kB 11.418 kB	37.713 kB 11.46 kB	-409 B 42 B
tabster focusable.findPrev	38.122 kB 11.418 kB	37.713 kB 11.46 kB	-409 B 42 B
tabster getCrossOrigin	107.424 kB 29.275 kB	105.836 kB 29.194 kB	-1.588 kB -81 B
tabster getDeloser	47.459 kB 13.693 kB	46.87 kB 13.723 kB	-589 B 30 B
tabster getGroupper	45.2 kB 13.071 kB	44.665 kB 13.109 kB	-535 B 38 B
tabster getModalizer	47.125 kB 13.835 kB	46.631 kB 13.859 kB	-494 B 24 B
tabster getMover	52.657 kB 15.331 kB	51.898 kB 15.332 kB	-759 B 1 B
tabster getObservedElement	43.877 kB 12.978 kB	43.416 kB 13.02 kB	-461 B 42 B
tabster getOutline	46.733 kB 13.653 kB	46.132 kB 13.682 kB	-601 B 29 B
tabster getRestorer	40.683 kB 12.006 kB	40.275 kB 12.054 kB	-408 B 48 B

_{🤖 This report was generated against 711667861375e72636f73d33df9c8d8644ae45cd}

[Copilot]

Pull request overview

This PR refactors Tabster’s internal use of window timer APIs to route through new free-function helpers in src/Utils.ts, allowing minification to mangle helper names (and avoid preserving .setTimeout/.clearTimeout property names) while enforcing the pattern via ESLint.

Changes:

• Added Timer handle type plus setTimer, clearTimer, and isTimerActive helpers in src/Utils.ts.
• Converted timer usage across src/**/*.ts to use the new helpers instead of direct .setTimeout/.clearTimeout calls.
• Updated eslint.config.mjs to restrict .setTimeout/.clearTimeout usage outside src/Utils.ts.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Utils.ts	Introduces Timer and the timer helper functions; updates existing instance-context timer usage.
src/Tabster.ts	Migrates core init/cleanup timers to Timer + helpers.
src/State/ObservedElement.ts	Converts waiting/condition timers to Timer handles and helper calls.
src/State/FocusedElement.ts	Migrates async focus and tabbing timers to helper API.
src/Root.ts	Converts focus/blur debounce timer to helper API.
src/Outline.ts	Converts outline update scheduling timer to helper API.
src/Mover.ts	Migrates mover scheduling/update timers and ignored-input timer to helper API.
src/Modalizer.ts	Converts hidden update and restore-focus timers to helper API.
src/Groupper.ts	Converts groupper update timer to helper API.
src/DummyInput.ts	Migrates dummy-input disposal and observer scheduling timers to helper API.
src/Deloser.ts	Converts restore-focus timer to helper API.
src/CrossOrigin.ts	Migrates cross-origin transaction, ping, and blur timers to helper API.
eslint.config.mjs	Adds no-restricted-syntax rules to prevent raw .setTimeout/.clearTimeout calls in src/**.

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