fix: preserve Windows input paths with glob-special segment names

[gilangabdian]

Summary

fixes #23383

On Windows, paths like D:\desk\test\@src\whatever.html or D:\desk\test\[id]\page.html
crash Vite with [UNRESOLVED_ENTRY].

Root Cause

unescapeGlobCharacters() calls isDynamicPattern(value) on the raw input before
any Windows check. On Windows, \ is the path separator — not an escape character —
so D:\test\[id] is misinterpreted as a glob pattern and throws.

// Before
function unescapeGlobCharacters(value: string): string {
  if (isDynamicPattern(value)) { // ← crashes for D:\test\[id]
    throw new Error(...)
  }
  // isWindows check never reached for paths with [ or (
}

Fix

Add if (isWindows) return value at the top of unescapeGlobCharacters to skip all glob processing on Windows (backslash is a path separator, not an escape character).
Refine escapedGlobCharactersRE to only match extglob modifiers (@, +, !) when followed by (, aligning with tinyglobby's extglob support.
Add a hasUnescapedGlob helper that strips valid escapes before calling isDynamicPattern, so valid glob escapes on POSIX are handled correctly.

Other PRs / Alternatives

There is an existing local branch chris/fix/windows-input-glob-unescape with a similar approach. However, it places if (isWindows) after isDynamicPattern(value), so paths with [ or ( segments (e.g. D:\test\[id]\page.html) still crash. Our fix places the guard at the very top, making it work for all glob-special characters.

i also add a unit test to make sure this change is saved and doesn't break the existing codebase:
Added unit tests in config.spec.ts (guarded by isWindows so they only run on Windows CI) covering all affected path patterns:

• D:\desk\test\@src\whatever.html
• D:\desk\test\!notes\page.html
• D:\desk\test\+draft\page.html
• D:\desk\test\(draft)\page.html ← would still fail with the other approach
• D:\desk\test\[id]\page.html ← would still fail with the other approach