fix(block): notify changes from native select elements

[Sawtone]

Fixes #2975.

Native <select> value changes do not produce DOM mutations, so selecting an option can update a Tool's saved data without triggering onChange. This PR routes native select changes through the existing Block update pipeline.

The listener is delegated to the Block holder, supporting multiple selects and replacement Tool roots. It runs during bubbling so the Tool's own change handler updates its state before updated() runs. Registration is synchronous and removal happens in Block.destroy(), preventing deferred initialization from reinstalling this listener after destruction.

Validation

• onchange.cy.ts: 30/30 passed with Cypress 13.13.3 and Electron 118 against a temporary Vite source fixture with a module-load wait.
• Chromium checks confirmed correct Tool callback ordering and select listener cleanup, including destruction before deferred initialization.
• ESLint on all four changed files: 0 errors, 6 existing warnings.
• git diff --check passed.

The temporary test runner and source fixture changes are not included in this PR. The production build and full cross-browser suite were not run locally.

Credits

The SelectTool fixture and initial regression tests are adapted from Sion612/editor.js#1. Thanks @Sion612 for that work.

Additional coverage checks composite Tools, Tool callback ordering, and destruction before deferred initialization.

[Copilot]

🟢 Approval recommended

No unresolved review issues were identified.

Pull request overview

Fixes native <select> change detection so Tool updates trigger the existing Block pipeline and onChange callbacks.

Changes:

• Adds delegated select-change handling and lifecycle cleanup.
• Adds regression coverage for ordering, replacement roots, composite Tools, and destruction.
• Adds select-based Cypress fixtures.

File summaries

File	Description
test/cypress/tests/onchange.cy.ts	Adds regression and lifecycle tests.
test/cypress/fixtures/tools/SelectTool.ts	Adds a basic select fixture.
test/cypress/fixtures/tools/CompositeSelectTool.ts	Adds a multi-select fixture.
src/components/block/index.ts	Implements select event handling and cleanup.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 0
• Review effort level: Lite

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[neSpecc]

Seems ok for me, please, increment a patch version and add a line in a changelog

[Sawtone]

@neSpecc Done~ bumped the patch version to 2.31.7 and added a changelog entry in df75108. Thanks for reviewing! Thanks @Sion612 for your help as well!