fix(desktop): Validate WSL node version against engine range after probe success

[UtkarshUsername]

Fixes #3611

What Changed

After the WSL preflight probe succeeds, the app now checks that the WSL Node version satisfies the server's requirement before accepting it as valid.

I tested this by downgrading my WSL node version to 18.19.1. The app correctly showed the failure, and suggested to upgrade node.

Why

When nvm's default Node version (e.g. 18.x) falls outside the server's engine range, the preflight probe still exits successfully and returns a valid node path. The server then silently exits because it can't run on that Node version, leaving the app stuck on "Connecting to WSL…". This adds a missing validation step to catch that case early and show the user a clear error.

Before:

The app got stuck in "Connecting to WSL…".

After:

Connecting to WSL fails, error is shown, and then the app falls back to Windows-backend mode.

Checklist

• This PR is small and focused
• I explained what changed and why
• I included before/after screenshots for any UI changes
• I included a video for animation/interaction changes

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Note

Medium Risk
Changes WSL backend selection preflight so previously successful probes can fail fatally; incorrect semver handling could block compatible setups, but scope is limited to desktop WSL startup validation.

Overview
WSL preflight no longer treats a successful node-pty probe as sufficient when the distro’s Node is too old for the bundled server. The probe script now emits a nodeVersion: line, parseNodeVersion reads it from stdout, and ensureNodePtyImpl compares that version to options.nodeEngineRange with satisfiesSemverRange before returning success.

If the version is outside the required range, the check returns a fatal failure with an explicit upgrade message instead of proceeding and leaving the app stuck on “Connecting to WSL…”. Unit tests cover parseNodeVersion parsing and trimming behavior.

^{Reviewed by Cursor Bugbot for commit 1e9bca3. Bugbot is set up for automated code reviews on this repo. Configure here.}

Note

[!NOTE]

Validate WSL Node.js version against engine range after probe success

• Extends the WSL node-pty probe script to output the detected Node.js version (nodeVersion: line) alongside the existing nodePath and resolvedPath lines.
• Adds parseNodeVersion to extract that version from probe stdout.
• After a successful probe, ensureNodePtyImpl checks the detected version against options.nodeEngineRange using satisfiesSemverRange, returning a fatal failure if the version does not satisfy the range.
• Behavioral Change: a previously successful probe can now return a fatal failure when the WSL Node.js version is outside the required engine range.

^{Macroscope summarized 1e9bca3.}

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[macroscopeapp]

Approvability

Verdict: Needs human review

Introduces a new fatal error pathway for WSL Node.js version validation. Previously-passing probes can now fail if the version doesn't satisfy the engine range. This behavioral change, plus the author being new to this file, warrants human review.

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