Remove stale goenv shims from v2 installations during upgrade to v3

[AdamDrewsTR]

No description provided.

[Copilot]

Pull request overview

Adds logic to detect and remove a stale goenv shim left behind by v2 installations during upgrades to v3. The stale shim (a bash wrapper that hard-codes a Homebrew Cellar libexec/goenv path baked in at rehash time) shadows the new v3 binary on PATH, so the cleanup is wired into the four entry points users may take to install/upgrade. The PowerShell installer is also rewritten with Join-Path, a more robust Write-ColorOutput, TLS 1.2, and an auto-profile setup step.

Changes:

• Detect v2 shim by content match on libexec/goenv and remove it from install.sh, install.ps1, scripts/swap/main.go, and cmd/root.go (PersistentPreRun).
• Refactor install.ps1 to use Join-Path, force TLS 1.2, switch to Write-Host-based color output, and add Initialize-PowerShellProfile.

Reviewed changes

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

File	Description
install.sh	Adds post-install removal of v2 shim using grep fingerprint check.
install.ps1	Adds shim cleanup, TLS 1.2 enforcement, Join-Path-based path building, refactored color output, and PowerShell profile auto-config.
scripts/swap/main.go	Removes stale v2 shim after swapping the goenv binary, falling back to ~/.goenv when GOENV_ROOT is unset.
cmd/root.go	In PersistentPreRun, silently removes a stale v2 goenv shim if found in the shims directory.

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[Copilot]

Pull request overview

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