fix!: replace unmaintained, insecure ts-node with tsx

[serhalp]

Summary

ts-node has unresolvable transitive security warnings and has been unmaintained for ~4 years.
tsx is a drop-in replacement that uses esbuild for fast TypeScript on-the-fly execution.

What changes

ts-node was only used for a single scenario in production code.

For local Build Plugins written in TypeScript (local .ts files referenced in netlify.toml):

Behavior	Before (ts-node)	After (tsx)
Transpilation	✅	✅
Execution	✅	✅
Type checking at load time	✅	❌

Plugins with type errors will now load successfully and may fail at runtime instead of at load time. Implicit type-checking was an undocumented feature and is removed in this PR. It is not consistent with the behaviour of Netlify Functions and Netlify Edge Functions .ts files. And relatively very few users use local Build Plugins to begin with, let alone .ts ones.

Module loading strategy

ts-node only supported CommonJS, so the old code used require() to load TS plugins:

if (tsNodeService !== undefined) {
  return require(pluginPath)
}

tsx supports both module systems natively, so we now use import() for all plugins (TS or not) and
register both loaders:

registerESM()  // hooks into Node's ESM loader for import()
registerCJS()  // hooks into Node's CJS loader for nested require() calls

Registration API differences:

Aspect	ts-node	tsx
register() returns:	Service object with config access	Unregister function (not needed)
Config introspection	tsNodeService.config.raw.compilerOptions	Not available nor needed
ESM/CJS handling	CJS only via require()	Separate registerESM() + registerCJS()

The service object was used to enrich error messages with the resolved tsconfig.
This is no longer possible with tsx, so addTsErrorInfo() has been removed.

Technical changes

• Replaced ts-node with tsx in @netlify/build
• Removed ts-node from @netlify/api devDependencies (this was unused)
• Replaced a single use of ts-node in a @netlify/build-info test
• Removed addTsErrorInfo() and tsNodeService parameter threading, as this existed only to
  augment type-checking error details (no longer a thing at all)
• Deleted tests that asserted type-checking behavior
• Not quite related, but this PR also includes an npm audit fix that resolves a glob security warning

[github-actions]

This pull request adds or modifies JavaScript (.js, .cjs, .mjs) files.
Consider converting them to TypeScript.

[serhalp]

compatible with our >=18.14.0 range: https://github.com/privatenumber/tsx/blob/3a3a0071c78eee94b7c73776729389e38056c21a/package.json#L69-L71

[serhalp]

This doesn't add any subdependencies, as we already use esbuild@0.27.2 just like tsx: https://node-modules.dev/grid/depth#install=esbuild@0.27.2+tsx@^4.21.0.
It does add ~600 KB for tsx itself.
But we save ~2 MB from removing ts-node: https://node-modules.dev/chart#selected=ts-node@10.9.2&install=ts-node (note: we won't save the 23 MB from typescript because we depend on it elsewhere).

[serhalp]

transitive dep with a CVE

[serhalp]

unrelated other CVE