refactor(js): delegate timers and DOM adapters to plinth

[GG-O-BP]

Summary

• add Plinth 0.11.0 and delegate timer operations to plinth/javascript/global
• delegate covered DOM operations to plinth/browser/element while preserving Glendix's public handle types and Option-returning selector API
• retain only documented compatibility FFI for native click, default scrollIntoView(), and typed identity bridges
• add timer and DOM contract tests covering execution, cancellation, every existing DOM operation, selector hit/miss, rectangle values, and scroll defaults

Verification

• ./scripts/verify.sh inner glendix — passed; 95 Glendix tests
• ./scripts/verify.sh final — passed
  • all family format/check/warnings/docs/style/FFI/boundary/generated gates
  • all standalone consumers and package tests
  • Glendam browser integration tests
  • widget .mpk build and inspection
  • Lustre browser E2E
  • Mendix 11.12.0 build, runtime, and browser E2E
• ./scripts/dependency-mode.sh check-commit glendix 8abeed8eb715b51a752aeef8ef6591537305d793 — passed

Closes #17