fix(linter/no-shadow): respect env settings when builtinGlobals is enabled

[vvnikita74]

Summary

Fixes a bug where no-shadow with builtinGlobals: true incorrectly reported shadowing of globals from ALL environments, ignoring the env configuration.

Before: is_builtin_global_name checked all environments in GLOBALS.values().

After: Only checks environments enabled via ctx.env().

Changes

• Modified is_builtin_global_name in no_shadow/mod.rs to iterate only over enabled environments
• Added tests for single and multiple environment configurations
• Updated snapshots

Test Cases

• env: { browser: true } with builtinGlobals: true reports window, document, top (browser globals)
• env: { browser: true } with builtinGlobals: true does NOT report Form (prototypejs), removeFile (mongo)
• env: { browser: true, node: true } reports both browser and node globals

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AI Usage Disclosure: This PR was developed with AI assistance (Claude Code) for code analysis and test generation. The changes have been reviewed and tested by the contributor.

[Sysix]

I could not find accessing the global in the original rule:

• https://github.com/eslint/eslint/blob/main/lib/rules/no-shadow.js
• https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/eslint-plugin/src/rules/no-shadow.ts

It only looks at the global scope, not inside the user configuration?

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 52 skipped benchmarks¹

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_{Comparing vvnikita74:fix/no-shadow-respect-env-settings (426dc96) with main (6bb502f)}

Footnotes

1. 52 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[camc314]

Thank you!