refactor-jasmine-vitest schematic fails on Windows with ENOENT error when creating markdown report

[narci90]

Command

generate

Is this a regression?

• Yes, this behavior used to work in the previous version

The previous version in which this bug was not present was

No response

Description

The refactor-jasmine-vitest schematic fails on Windows when attempting to create the markdown report file. The schematic generates a filename with an ISO timestamp (e.g., jasmine-vitest-2026-01-19T08:13:16.971Z.md) which contains colons (:) that are invalid characters for Windows filenames.

This is a cross-platform compatibility issue - the schematic works fine on Unix-based systems (Linux/macOS) but fails on Windows.

Minimal Reproduction

1. Create a new Angular project with Jasmine tests:

ng new test-project
cd test-project

2. Run the refactor-jasmine-vitest schematic:

ng generate @schematics/angular:refactor-jasmine-vitest

Output:

    Jasmine to Vitest Refactoring Summary:
    - 1 test file(s) scanned.
    - 1 file(s) transformed.
Error: ENOENT: no such file or directory, open 'C:\projects\test-project\jasmine-vitest-2026-01-19T08:13:16.971Z.md'

Exception or Error

Error: ENOENT: no such file or directory, open 'C:\projects\test-project\jasmine-vitest-2026-01-19T08:13:16.971Z.md'
at Object.openSync (node:fs:590:3)
at Object.writeFileSync (node:fs:2294:35)
at StandardFileSystemTree.create (C:\projects\test-project\node_modules@angular-devkit\schematics\src\tree\filesystem.js:156:26)

Your Environment

Angular CLI       : 21.1.0
Angular           : 21.1.0
Node.js           : 24.12.0
Package Manager   : npm 11.6.2
Operating System  : win32 x64

┌───────────────────────────┬───────────────────┬───────────────────┐
│ Package                   │ Installed Version │ Requested Version │
├───────────────────────────┼───────────────────┼───────────────────┤
│ @angular/build            │ 21.1.0            │ ^21.1.0           │
│ @angular/cli              │ 21.1.0            │ ^21.1.0           │
│ @angular/common           │ 21.1.0            │ ^21.1.0           │
│ @angular/compiler         │ 21.1.0            │ ^21.1.0           │
│ @angular/compiler-cli     │ 21.1.0            │ ^21.1.0           │
│ @angular/core             │ 21.1.0            │ ^21.1.0           │
│ @angular/forms            │ 21.1.0            │ ^21.1.0           │
│ @angular/platform-browser │ 21.1.0            │ ^21.1.0           │
│ @angular/router           │ 21.1.0            │ ^21.1.0           │
│ rxjs                      │ 7.8.2             │ ~7.8.0            │
│ typescript                │ 5.9.3             │ ~5.9.2            │
│ vitest                    │ 4.0.17            │ ^4.0.8

Anything else relevant?

No response