fix: add shell option to npm spawn on Windows

[veerababu1729]

Description

Fixes Windows-specific EINVAL error when spawning npm install commands.

Problem

On Windows, the run_npm_install function in Kernel.js was failing with spawn EINVAL error because it was missing the shell: true option when spawning npm.cmd.

Solution

• Added shell: true to spawn options in run_npm_install function
• Makes the spawn call consistent with other spawn calls in the codebase (ProcessService.js and LocalTerminalService.js)
• Cross-platform compatible (works on Windows, Linux, macOS)

Changes

• File: src/backend/src/Kernel.js
• Line: 581
• Change: Added shell: true to spawn options

Fixes

• Closes Windows Error #1748
• Closes Invalid Host header. & workers error #1797

Why Windows Needs shell: true:

• On Windows, npm.cmd is a batch file, not an executable
• Node.js spawn() cannot execute .cmd files directly without shell: true
• Without it, Windows throws EINVAL (Invalid argument) error

Proof from Codebase:
Other spawn calls in the same codebase already use shell: true:

• ProcessService.js line 76: spawn(command, args, { shell: true, ... })
• LocalTerminalService.js line 93: spawn(profile.shell[0], args, { shell: true, ... })

Testing

• Verified fix follows existing code patterns in the codebase
• Minimal change with low risk
• No functional changes to other parts of the system

Type of Change

• Bug fix (non-breaking change which fixes an issue)

[CLAassistant]

All committers have signed the CLA.

[veerababu1729]

I almost worked one day to find this, please review as soon as possible and feel free to ask anything...

[jelveh]

Hey @veerababu1729. thank you for you PR. I've assigned @ProgrammerIn-wonderland to review this. Please stay tuned.

[ProgrammerIn-wonderland]

I think @KernelDeimos mentioned on call that we shouldn't do (shell: true) since it says a deprecation warning in shell but I'll check if that's still the case