[Bug]: Source control (Azure DevOps): VcsProcessSpawnError on Windows because Node child_process.spawn cannot resolve `az.cmd`

[kilyess]

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Install Azure CLI 2.86.0 on Windows; verify az --version works in cmd.exe.
2. Install the azure-devops extension and run az login; verify az repos pr list --detect true --top 1 --output json works in cmd.exe inside an ADO repo.
3. Open T3 Code.
4. Click the "Create PR" button.
5. Server log shows Source control provider azure-devops failed in listChangeRequests: VcsProcessSpawnError followed by VCS process failed to spawn in AzureDevOpsCli.execute: az repos pr list --detect true --source-branch <branch> --status active --top 1 --only-show-errors --output json (<cwd>). The Create PR flow never opens.
6. Outside T3 Code: node -e "require('child_process').spawnSync('az', ['--version'], {stdio:'inherit'})" fails silently with spawn az ENOENT; same call with {shell:true} works (Node 22+ also prints DEP0190 deprecation).

Expected behavior

On Windows, T3 Code resolves az (and any other .cmd/.bat-shimmed CLI such as gh, glab, npm) the same way cmd.exe does — by consulting PATHEXT and falling through to az.cmd. Source control discovery for Azure DevOps succeeds when az + the azure-devops extension are installed and authenticated.

Actual behavior

On Windows, every spawn of az fails before the child process starts. T3 Code surfaces a generic VcsProcessSpawnError with no install hint, even though az is on PATH and works in cmd.exe / PowerShell. The reactive error classifier in AzureDevOpsCli.ts ("command not found: az", "enoent", etc.) never runs because the failure happens at the child_process.spawn boundary inside the Effect platform-node spawner, not inside az itself. Result: Azure DevOps integration is completely unusable on Windows hosts.

Impact

Major degradation or frequent failure

Version or commit

main @ f4c9418

Environment

Windows 11 Pro, T3 Code Alpha v0.0.22, Node v24.11.1

Logs or stack traces

Source control provider azure-devops failed in listChangeRequests: VcsProcessSpawnError
VCS process failed to spawn in AzureDevOpsCli.execute: az repos pr list --detect true --source-branch <branch> --status active --top 1 --only-show-errors --output json (<cwd>)


Reproduction outside T3 Code (Node only):


> node -e "const r = require('child_process').spawnSync('az', ['--version']); console.log(JSON.stringify({status: r.status, error: r.error && r.error.message, stderr: r.stderr.toString()}, null, 2))"
{
  "status": null,
  "error": "spawn az ENOENT",
  "stderr": ""
}

> node -e "const r = require('child_process').spawnSync('az', ['--version'], {shell: true}); console.log(JSON.stringify({status: r.status, stdoutSnippet: r.stdout.toString().slice(0,40)}, null, 2))"
(node:50260) [DEP0190] DeprecationWarning: Passing args to a child process with shell option true can lead to security vulnerabilities, as the arguments are not escaped, only concatenated.
{
  "status": 0,
  "stdoutSnippet": "azure-cli                         2.86.0"
}

Screenshots, recordings, or supporting files

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Workaround

No response