fix(frontend): make development label detection cross-platform (#6988)

# Description of Changes

This PR makes the frontend development label detection compatible with
both Windows and Unix-based environments.

- Added platform-specific handling to the `STIRLING_DEV_LABEL` Taskfile
variable.
- Uses PowerShell and `Split-Path` on Windows.
- Retains the existing `basename` implementation on Linux and macOS.
- Preserves the fallback to the current working directory when the Git
repository root cannot be determined.
- Fixes `task frontend:dev` and `task dev:all` failing on Windows
because `basename` was unavailable.
- Handles shell quoting explicitly so PowerShell variables are not
expanded by the intermediate command shell.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### Translations (if applicable)

- [ ] I ran
[`scripts/counter_translation.py`](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/docs/counter_translation.md)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have run `task check` to verify linters, typechecks, and tests
pass
- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#7-testing)
for more details.

.taskfiles/frontend.yml

@@ -85,7 +85,8 @@ tasks:
       # full path, hostname, or user. Consumed at dev-serve time by vite.config
       # and dropped from production builds.
       STIRLING_DEV_LABEL:
-        sh: basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
+        sh: >-
+          {{if eq OS "windows"}}powershell -NoProfile -Command '$root = git rev-parse --show-toplevel 2>$null; if (-not $root) { $root = (Get-Location).Path }; Split-Path -Leaf $root'{{else}}basename "$(git rev-parse --show-toplevel 2>/dev/null || pwd)"{{end}}
     cmds:
       - npx vite editor --mode {{.MODE}} --port {{.PORT}}{{if .OPEN}} --open{{end}}