fix: detect homebrew cask installs

internal/version/install_method.go

@@ -21,13 +21,22 @@ type InstallInfo struct {
 }
 
 const rawInstallCommand = "curl -sSL https://github.com/groundsgg/grounds-cli/releases/latest/download/install.sh | bash"
+const homebrewFormulaUpdateCommand = "brew upgrade groundsgg/tap/grounds"
+const homebrewCaskUpdateCommand = "brew upgrade --cask groundsgg/tap/grounds"
 
 func DetectInstallMethod(executablePath, homeDir string) InstallInfo {
 	normalized := normalizePath(executablePath)
+	if resolved, err := filepath.EvalSymlinks(executablePath); err == nil {
+		normalized = normalizePath(resolved)
+	}
 	home := normalizePath(homeDir)
 
 	if strings.Contains(normalized, "/homebrew/cellar/") || strings.Contains(normalized, "/cellar/grounds/") {
-		return InstallInfo{Method: InstallHomebrew, UpdateCommand: "brew upgrade groundsgg/tap/grounds"}
+		return InstallInfo{Method: InstallHomebrew, UpdateCommand: homebrewFormulaUpdateCommand}
+	}
+
+	if strings.Contains(normalized, "/caskroom/grounds/") {
+		return InstallInfo{Method: InstallHomebrew, UpdateCommand: homebrewCaskUpdateCommand}
 	}
 
 	if strings.Contains(normalized, "/scoop/apps/grounds/") {

internal/version/install_method_test.go

@@ -1,6 +1,10 @@
 package version
 
-import "testing"
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
 
 func TestDetectInstallMethod(t *testing.T) {
 	tests := []struct {
@@ -16,6 +20,17 @@ func TestDetectInstallMethod(t *testing.T) {
 			wantMethod:  InstallHomebrew,
 			wantCommand: "brew upgrade groundsgg/tap/grounds",
 		},
+		{
+			name:        "homebrew cask linux target",
+			path:        "/home/linuxbrew/.linuxbrew/Caskroom/grounds/0.1.14/grounds",
+			wantMethod:  InstallHomebrew,
+			wantCommand: "brew upgrade --cask groundsgg/tap/grounds",
+		},
+		{
+			name:       "homebrew prefix bin path without resolved target is unknown",
+			path:       "/tmp/nonexistent-homebrew-prefix/bin/grounds",
+			wantMethod: InstallUnknown,
+		},
 		{
 			name:        "scoop",
 			path:        `C:\Users\Lukas\scoop\apps\grounds\current\grounds.exe`,
@@ -67,3 +82,32 @@ func TestDetectInstallMethod(t *testing.T) {
 		})
 	}
 }
+
+func TestDetectInstallMethodResolvesHomebrewCaskSymlink(t *testing.T) {
+	root := t.TempDir()
+	targetDir := filepath.Join(root, "Caskroom", "grounds", "0.1.14")
+	if err := os.MkdirAll(targetDir, 0o755); err != nil {
+		t.Fatalf("create target dir: %v", err)
+	}
+	target := filepath.Join(targetDir, "grounds")
+	if err := os.WriteFile(target, []byte("binary"), 0o755); err != nil {
+		t.Fatalf("create target: %v", err)
+	}
+
+	binDir := filepath.Join(root, "bin")
+	if err := os.MkdirAll(binDir, 0o755); err != nil {
+		t.Fatalf("create bin dir: %v", err)
+	}
+	link := filepath.Join(binDir, "grounds")
+	if err := os.Symlink(target, link); err != nil {
+		t.Fatalf("create symlink: %v", err)
+	}
+
+	got := DetectInstallMethod(link, "")
+	if got.Method != InstallHomebrew {
+		t.Fatalf("method = %q, want %q", got.Method, InstallHomebrew)
+	}
+	if got.UpdateCommand != homebrewCaskUpdateCommand {
+		t.Fatalf("update command = %q, want %q", got.UpdateCommand, homebrewCaskUpdateCommand)
+	}
+}