fix: align esX browserslist expression to caniuse

[fi3ework]

Summary

previously, esX's browserslist expression came from esbuild's table, but esbuild's browser version was relative higher (for example, ES2015 supports dynamic import, so Chrome's minimum version was raised to 63 https://github.com/evanw/esbuild/blob/main/internal/compat/js_table.go#L470).

here, we use data from caniuse to ensure a fix.

Related Links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[Copilot]

Pull Request Overview

This PR updates the ESX to browserslist version mappings to align with caniuse data instead of esbuild's compatibility table. The change lowers minimum browser version requirements for ES2015-ES2023, as esbuild's table used higher versions based on specific features like dynamic imports, while caniuse reflects broader ES version support.

Key Changes:

• Updated browser version mappings for ES6/ES2015 through ES2023 in the ESX_TO_BROWSERSLIST configuration
• Added Samsung browser to the browserslist mappings
• Updated tests and snapshots to reflect the new, lower minimum browser versions

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
packages/core/src/utils/syntax.ts	Updated ESX_TO_BROWSERSLIST mappings with lower browser versions from caniuse data; removed outdated comments about esbuild source
packages/core/tests/syntax.test.ts	Updated test expectations to reflect new ES2015 and ES2018 browserslist versions
packages/core/tests/config.test.ts	Updated snapshot for ES2015 browserslist configuration
tests/integration/syntax/fixtures/src/index.ts	Added object spread syntax test case to fixture
tests/integration/syntax/index.test.ts	Added assertions to verify spread operator transpilation behavior
tests/integration/syntax/snapshots/index.test.ts.snap	Updated snapshots with new transpilation output including spread operator helpers
tests/integration/cli/build/build.test.ts	Updated snapshot reflecting const to var transpilation change

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}