Fix off-by-one in expandShortPathNative truncating last path character on Windows

[Copilot]

GetLongPathNameW returns the output string length excluding the null terminator, but the buffer slice used (result - 1) * 2, silently dropping the last character of every expanded path (e.g. textfile-with~tilde.txt → textfile-with~tilde.tx).

This bug was latent until koffi 2.15.2 fixed its install script (18467bcc): -p/-d flags in the packaged install script were changed to the correct -P/-D, so the prebuilt native addon is now properly installed and koffi/indirect loads successfully. In 2.15.1, koffi/indirect failed to load (caught silently), masking the bug.

Fix:

- const longPath = buffer.toString("utf16le", 0, (result - 1) * 2);
+ const longPath = buffer.toString("utf16le", 0, result * 2);

[Copilot]

Pull request overview

Fixes a Windows-specific path expansion bug in expandShortPathNative where the last character of the expanded path was being truncated due to an off-by-one error when converting the UTF-16 buffer returned by GetLongPathNameW.

Changes:

• Correct the buffer slice length used when decoding the GetLongPathNameW result (length excludes the null terminator, so no - 1 is needed).

Show a summary per file

File	Description
extensions/ql-vscode/src/common/short-paths.ts	Fixes UTF-16 buffer decoding length to avoid truncating the last character of expanded Windows paths.

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