Fix Windows Qt launcher for Visual Studio 2026

[masarray]

Fix the ARStack Studio Windows launcher after a real VS2026 workstation failure.

Root cause:

• the launcher treated PATH case-sensitively while importing VsDevCmd output;
• Path could therefore be discarded, leaving CMake unable to locate cl.exe;
• user-facing text also incorrectly implied Visual Studio 2022 was required.

Changes:

• discover the newest Visual Studio x64 C++ toolchain generically with vswhere, including VS2026/v145 and prerelease channels;
• import the complete developer environment case-insensitively;
• verify cl.exe before CMake and pass the compiler explicitly;
• add CMake/Ninja detection fallbacks and diagnostics;
• clear only a broken CMAKE_CXX_COMPILER-NOTFOUND cache;
• add optional -VisualStudioRoot override;
• clarify that Qt's msvc2022_64 folder is the Qt kit name, not a requirement to install the VS2022 IDE.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: c2f44ab2d2

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Skip vswhere validation when an explicit root is supplied

When -VisualStudioRoot points to a valid installation but vswhere.exe is absent or unavailable, the launcher still throws at the unconditional validation on lines 15–18 before reaching this override branch. This defeats the new manual override precisely in environments where automatic discovery cannot be used; only require and invoke vswhere in the else branch.

Useful? React with 👍 / 👎.