Debug Test uses file directory as cwd instead of workspace root

[whisper-bye]

When running Zig tests from the VS Code extension:

• The Run profile uses the workspace folder as cwd (via getWorkspaceFolder(...)), which matches how zig test is usually run from the project root.
• The Debug profile always uses the test file directory as cwd.

In src/zigTestRunnerProvider.ts, debugTest builds the test binary and then starts the debugger with:

const debugConfig: vscode.DebugConfiguration = {
    type: debugAdapter,
    name: `Debug ${testItem.label}`,
    request: "launch",
    program: testBinaryPath,
    cwd: path.dirname(testItem.uri.fsPath),
    stopAtEntry: false,
};

This makes std.fs.cwd() inside tests differ between Run and Debug (e.g. .../project/src vs .../project), and there is currently no setting to change this behavior (e.g. zig.debugTestArgs does not affect cwd).