fix(css): include file name in CSS minification warnings and errors

[AliMahmoudDev]

Summary

Fixes #15915

CSS minification warnings from both esbuild and lightningcss currently do not include the source file name in the warning/error message. This makes it extremely difficult to track down which CSS file caused the issue, especially in large projects with many CSS modules.

Before:

[esbuild css minify]
WARNING: Unexpected "{" (note: this is a CSS nesting feature)

  <stdin>:5:1:
    3 │   }
    4 │   div[id*="app"] {
  > 5 │     color: red;

After:

[esbuild css minify]
components/App.module.css: WARNING: Unexpected "{" (note: this is a CSS nesting feature)

  <stdin>:5:1:
    3 │   }
    4 │   div[id*="app"] {
  > 5 │     color: red;

Changes

• esbuild warnings: Prepend file: prefix from warning.location.file to each formatted warning message
• esbuild errors: Include filename in error message
• lightningcss warnings: Include filename in the [lightningcss minify] prefix
• lightningcss errors: Include filename in error message

Before/After Comparison

Minifier	Before	After
esbuild warn	[esbuild css minify]\nWARNING: Unexpected "{"	[esbuild css minify]\nstyle.css: WARNING: Unexpected "{"
lightningcss warn	[lightningcss minify] Unexpected nesting	[lightningcss minify] style.css\n Unexpected nesting
esbuild error	[esbuild css minify] ERROR: ...	[esbuild css minify] style.css\n ERROR: ...
lightningcss error	[lightningcss minify] ERROR: ...	[lightningcss minify] style.css\n ERROR: ...

[AliMahmoudDev]

Hi maintainers! Just wanted to note that the zizmor CI failure on this PR is caused by a pre-existing issue in .github/workflows/ecosystem-ci-trigger.yml (line 134 - actions/create-github-app-token without restricted permissions). The same finding appears when running zizmor on the main branch, so it is not introduced by this PR's CSS-related changes.

All other checks (Build & Test, Lint) are passing. The PR only modifies CSS minification warning/error formatting in packages/vite/src/node/minify.ts.