feat: add pkg (FreeBSD) and ports (OpenBSD) package manager implementations

pkg implements Manager, VersionQuerier, Cleaner, and FileOwner interfaces
wrapping FreeBSD's pkg(8) CLI. ports implements Manager wrapping OpenBSD's
pkg_add/pkg_delete/pkg_info tools.

Both use build tags (freebsd/openbsd) for real implementations with stub
files for other platforms. Includes parser tests for all output formats.

ports/parse.go

@@ -0,0 +1,116 @@
+package ports
+
+import (
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+// parseList parses the output of `pkg_info`.
+// Format: "name-version description text"
+func parseList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		// First field is name-version, rest is description
+		parts := strings.SplitN(line, " ", 2)
+		nameVer := parts[0]
+		name, ver := splitNameVersion(nameVer)
+		p := snack.Package{
+			Name:      name,
+			Version:   ver,
+			Installed: true,
+		}
+		if len(parts) == 2 {
+			p.Description = strings.TrimSpace(parts[1])
+		}
+		pkgs = append(pkgs, p)
+	}
+	return pkgs
+}
+
+// parseSearchResults parses the output of `pkg_info -Q <query>`.
+// Each line is a package name-version.
+func parseSearchResults(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		name, ver := splitNameVersion(line)
+		pkgs = append(pkgs, snack.Package{
+			Name:    name,
+			Version: ver,
+		})
+	}
+	return pkgs
+}
+
+// parseInfoOutput parses `pkg_info <pkg>` output.
+// The first line is typically "Information for name-version" or
+// the package description block. We extract name/version from
+// the stem or the provided pkg name.
+func parseInfoOutput(output string, pkg string) *snack.Package {
+	lines := strings.Split(output, "\n")
+	p := &snack.Package{Installed: true}
+
+	for _, line := range lines {
+		line = strings.TrimSpace(line)
+		if strings.HasPrefix(line, "Information for ") {
+			nameVer := strings.TrimPrefix(line, "Information for ")
+			nameVer = strings.TrimSuffix(nameVer, ":")
+			p.Name, p.Version = splitNameVersion(nameVer)
+			continue
+		}
+	}
+
+	// If we got description lines (after the header), join them
+	if p.Name != "" {
+		var desc []string
+		inDesc := false
+		for _, line := range lines {
+			trimmed := strings.TrimSpace(line)
+			if strings.HasPrefix(trimmed, "Information for ") {
+				inDesc = false
+				continue
+			}
+			if strings.HasPrefix(trimmed, "Comment:") {
+				p.Description = strings.TrimSpace(strings.TrimPrefix(trimmed, "Comment:"))
+				continue
+			}
+			if strings.HasPrefix(trimmed, "Description:") {
+				inDesc = true
+				continue
+			}
+			if inDesc && trimmed != "" {
+				desc = append(desc, trimmed)
+			}
+		}
+		if p.Description == "" && len(desc) > 0 {
+			p.Description = strings.Join(desc, " ")
+		}
+	}
+
+	if p.Name == "" {
+		// Fallback: try to parse from pkg argument
+		p.Name, p.Version = splitNameVersion(pkg)
+		if p.Name == "" {
+			return nil
+		}
+	}
+	return p
+}
+
+// splitNameVersion splits "name-version" at the last hyphen.
+// OpenBSD packages use the last hyphen before a version number as separator.
+func splitNameVersion(s string) (string, string) {
+	idx := strings.LastIndex(s, "-")
+	if idx <= 0 {
+		return s, ""
+	}
+	return s[:idx], s[idx+1:]
+}