Fix the suffix bug in Windows

[Qxy0happy]

This PR fixes the suffix bug on Windows.

[Copilot]

Pull request overview

This PR aims to fix a Windows-specific executable suffix issue when compiling/running exercises, and also updates the module’s Go/tooling dependencies.

Changes:

• Update exercise compilation to return a temp executable path (instead of an open file handle) and attempt to append .exe on Windows.
• Add additional error checks around CLI output printing.
• Bump go.mod Go version and upgrade several dependencies (with corresponding go.sum updates).

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 4 comments.

File	Description
cmd/gopherlings/main.go	Adjusts temp executable creation/execution flow and adds Windows-specific naming logic.
go.mod	Updates Go version directive and bumps direct/indirect dependencies.
go.sum	Updates checksums to match the dependency upgrades.

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[Copilot]

main no longer exits with a non-zero status when rootCmd.Execute() returns an error. After printing the error, the program falls through and returns exit code 0 unless printing fails, which will mask failures for callers/CI. Ensure the error path still calls os.Exit(1) (or returns an error to main).

Suggested change

	_, err = red.Fprintln(os.Stderr, err)
	if err != nil {
	os.Exit(1)
	}
	_, printErr := red.Fprintln(os.Stderr, err)
	if printErr != nil {
	os.Exit(1)
	}
	os.Exit(1)

[Copilot]

On Windows, appending .exe to the pattern passed to os.CreateTemp doesn't guarantee the resulting filename ends with .exe (CreateTemp appends random characters after the pattern unless you include *). This can still produce a non-executable path like foo.exe12345, so the Windows suffix issue likely persists. Use a pattern like name+"*.exe" (or create a temp dir and join name+".exe") so the final file actually has the .exe suffix.

Suggested change

	if runtime.GOOS == "windows" {
	name += ".exe"
	}
	f, err := os.CreateTemp("", name)
	pattern := name
	if runtime.GOOS == "windows" {
	pattern = name + "*.exe"
	}
	f, err := os.CreateTemp("", pattern)

[Copilot]

The result of f.Close() is ignored. Since the file must be closed on Windows before it can be executed/overwritten reliably, handle the close error and clean up the temp file on failure.

Suggested change

	f.Close()
	if err := f.Close(); err != nil {
	// Best-effort cleanup if we fail to close the temp file.
	_ = os.Remove(tmpPath)
	return "", err
	}

[Copilot]

The PR description is about a Windows suffix bug, but this change also bumps the module go version from 1.18 to 1.26 and updates multiple dependencies. Raising the go directive is a compatibility-breaking change for users/build environments pinned to older Go versions, so it should be justified in the PR (or reverted if not required for the fix).

[Qxy0happy]

@copilot apply changes based on this feedback

[soypat]

What is the windows suffix bug? @Qxy0happy

[Qxy0happy]

During the use of this tool, the following error was encountered:
gopherlings on git main via go v1.26.1 took 1m0s

.\cmd\gopherlings\gopherlings.exe watch
Compiling .\exercises\001-hello
Executing .\exercises\001-hello

exec: "D:\Cache\Temp\User\30625\001-hello633839467": executable file not found in %PATH%

Subsequent analysis indicates that this issue arises from the suffix automatically appended by the Windows operating system. Consequently, the program is unable to locate the file corresponding to f.Name().