Installer: drop redundant -WindowStyle Hidden from the Windows launcher VBS

[danielhanchen]

Summary

The Windows installer creates a desktop / Start Menu shortcut that launches Unsloth Studio windowlessly through a generated launch-studio.vbs:

Set shell = CreateObject("WScript.Shell")
cmd = "powershell -NoProfile -ExecutionPolicy Bypass -WindowStyle Hidden -File ""...launch-studio.ps1"""
shell.Run cmd, 0, False

The second argument to shell.Run is intWindowStyle = 0 (hidden), so WScript already starts the child windowless. The child -WindowStyle Hidden is therefore redundant. This drops it, which keeps the launcher hidden and the behaviour identical, and removes the "WScript spawns a hidden, ExecutionPolicy-Bypass PowerShell" token combination that antivirus heuristics weight. That shape was reported as a Kaspersky HEUR:Trojan.VBS.Agent false positive during install.

- cmd = "powershell -NoProfile -ExecutionPolicy Bypass -WindowStyle Hidden -File ""$launcherPs1"""
+ cmd = "powershell -NoProfile -ExecutionPolicy Bypass -File ""$launcherPs1"""

-ExecutionPolicy Bypass is kept on purpose: the locally generated, unsigned .ps1 must still run under the default Restricted machine policy.

Why this is a false positive (audit)

I scanned the exact launcher files the installer writes (the current baseline plus several hardening candidates) across Windows, macOS and Linux runners, and on VirusTotal:

Engine	Result on the current launcher
Microsoft Defender, real-time + cloud, verified live each run with an EICAR positive control, static (3 passes)	0 detections
Microsoft Defender, actually launched 5 times (wscript to hidden PowerShell)	0 detections
ClamAV (Windows, Linux, macOS)	clean
VirusTotal, ~70 engines including Kaspersky and Microsoft	0 / 60

Every engine is clean, both statically and at launch, confirmed across three independent Defender-live runs. The Kaspersky desktop detection is a transient heuristic / cloud-reputation false positive that does not reproduce in current engines; this change trims the heuristic footprint that produced it.

Tests

• New tests/studio/install/test_launch_studio_launcher.py asserts the generated VBS no longer passes -WindowStyle Hidden, still stays windowless via shell.Run(cmd, 0, False), and keeps -ExecutionPolicy Bypass -File.
• Existing tests/python/test_cross_platform_parity.py still passes.

Operational follow-up

Submitting the launcher to the Kaspersky and Microsoft false-positive / whitelist portals is recommended so the transient detection is cleared vendor-side as well.

[gemini-code-assist]

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