Fix Windows CI: normalize absolute paths in SCSS @use/@import/@forward for Sass compatibility

[Copilot]

Dart Sass misinterprets Windows drive letters (C:/) as URL schemes in @use/@import/@forward directives, causing "Can't find stylesheet to import" on Windows CI. Same root cause as Simon-He95/transformToUnoCSS#68. Aligned with fix patterns from transformToUnoCSS PR #67, #69, and #70.

• src/sassCompiler.ts: Before compilation, detect absolute Windows paths in SCSS import directives, extract the parent directory into loadPaths, and rewrite to just the basename

// @use "C:/Users/RUNNER~1/.../styles/tokens" as *;  ← Sass sees "C:" as URL scheme
// becomes:
// @use "tokens" as *;  ← loadPaths now includes the parent directory
const winAbsPathRegex = /@(use|import|forward)\s+(['"])([A-Za-z]:[/\\][^'"]+)\2/g
result = result.replace(winAbsPathRegex, (match, kw, quote, absPath) => {
  const dir = path.dirname(absPath.replace(/\//g, path.sep))
  if (!compileOptions.loadPaths.includes(dir))
    compileOptions.loadPaths.push(dir)
  return `@${kw} ${quote}${path.basename(absPath.replace(/\//g, path.sep))}${quote}`
})

• src/sassCompiler.ts: Return original CSS instead of undefined on Sass compilation errors, so that transformVue can still process the style block even when compilation fails (aligned with transformToUnoCSS PR chore(deps): update dependency stylus to v0.64.0 #70)

• test/sassCompiler.test.ts: Updated error case test expectation to match the new behavior of returning original CSS on failure

Original prompt

---

This section details on the original issue you should resolve

<issue_title>bug</issue_title>
<issue_description>这个issue：https://github.com/Simon-He95/transformToUnoCSS/pull/69#issuecomment-4132445310，的问题还是存在
下面是最新的ci的报错

RUN v3.2.4 D:/a/transformToTailwindcss/transformToTailwindcss

✓ test/classCollectorComplex.test.ts (16 tests) 22ms
✓ test/browserCompatibility.test.ts (8 tests) 518ms
✓ Browser environment compatibility > transformCss environment handling > should import transformCss without errors in Node.js environment 460ms
stdout | test/sassCompiler.test.ts > sassCompiler > should handle error cases gracefully
[transform-to-unocss] Compiling SCSS file: D:\a\transformToTailwindcss\transformToTailwindcss\test\demo\sass\error-test.scss

stderr | test/sassCompiler.test.ts > sassCompiler > should handle error cases gracefully
Error:
transform-to-unocss(sassCompiler) Can't find stylesheet to import.
╷
2 │ @use './non-existent-file';
│ ^^^^^^^^^^^^^^^^^^^^^^^^^^
╵
C:\Users\runneradmin\AppData\Local\Temp\transform-to-tailwindcss-1RrWOn\input.scss 2:7 root stylesheet

stderr | test/sassCompiler.test.ts > compilerCss file:// URL handling > should handle file:// URLs gracefully (may fail but should not crash)
stdout | test/sassCompiler.test.ts > compilerCss file:// URL handling > should handle file:// URLs gracefully (may fail but should not crash)
Error:
Processing CSS with file:// URL...
transform-to-unocss(sassCompiler) Can't find stylesheet to import.

╷
2 │ @use 'file:///some/absolute/path/to/styles.scss';
│ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
╵
C:\Users\runneradmin\AppData\Local\Temp\transform-to-tailwindcss-vt8aAw\input.scss 2:7 root stylesheet

✓ test/sassCompiler.test.ts (15 tests) 675ms
✓ sassCompiler > should compile basic SCSS 437ms
✓ test/classCollector.test.ts (11 tests) 23ms
stdout | ClassCollector.generateSafelistFile (D:\a\transformToTailwindcss\transformToTailwindcss\src\classCollector.ts:331:15)
[transform-to-tailwindcss] Generated safelist file: ./safelist-classes.js

stdout | ClassCollector.generateSafelistFile (D:\a\transformToTailwindcss\transformToTailwindcss\src\classCollector.ts:334:15)
[transform-to-tailwindcss] Collected 2 unique classes

stderr | test/transformCode.test.ts > transformCode > transformCode: all

• color: $brand-color;
• }</style>

❯ test/transformAstro.test.ts:59:20
57| })
58|
59| expect(result).toContain('text-red')
| ^
60| expect(result).not.toContain('$brand-color')
61|

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯[1/1]⎯

Test Files 1 failed | 10 passed (11)
Tests 1 failed | 81 passed (82)
Start at 09:28:10
Duration 5.88s (transform 480ms, setup 0ms, collect 5.26s, tests 4.61s, environment 4ms, prepare 2.07s)

Error: AssertionError: expected '---\nexport const prerender = true;\n…' to contain 'text-red'

• Expected

• Received

• text-red

• ---

• export const prerender = true;

• ---

• hi

• <style>@use "C:/Users/RUNNER~1/AppData/Local/Temp/transform-to-tailwindcss-astro-JMVbIb/src/styles/tokens" as *;
• .title {
• color: $brand-color;
• }</style>

❯ test/transformAstro.test.ts:59:20

 ELIFECYCLE  Test failed. See above for more details.
Error: Process completed with exit code 1.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes bug #84

---

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[Simon-He95]

@copilot 你应该关注一下下面几个pr的修复方案：

Simon-He95/transformToUnoCSS#70
Simon-He95/transformToUnoCSS#69
Simon-He95/transformToUnoCSS#67

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[Copilot]

@copilot 你应该关注一下下面几个pr的修复方案：

Simon-He95/transformToUnoCSS#70
...

Reviewed all three PRs and applied the same patterns:

1. PR chore(deps): update dependency @iconify/json to v2.2.401 #67 (.gitattributes eol=lf) — already present in this repo ✓
2. PR chore(deps): update dependency vue-use-monaco to ^0.0.33 #69/chore(deps): update dependency stylus to v0.64.0 #70 (Windows absolute path handling) — already applied in commit 1befa94 using the loadPaths approach to avoid drive-letter-as-URL-scheme issue
3. PR chore(deps): update dependency stylus to v0.64.0 #70 (error handler returns original CSS) — applied in commit 79cce7d. Changed return undefined to return css in sassCompiler's error handler so that transformVue can still process the style block even if Sass compilation fails. Updated the corresponding test expectation.