fix(detect): wire up ports package for OpenBSD detection

The ports package was fully implemented but detect_openbsd.go still
returned nil candidates with a stale TODO. Wire up ports.New() so
OpenBSD systems can auto-detect their package manager.

Also adds:
- Unit tests for GetCapabilities with mock managers (base + full)
- Unit tests for Locker mutual exclusion
- Edge case tests for ports parser (empty input, whitespace, fallback)
- Minor dep updates (charmbracelet/ultraviolet, charmbracelet/x)

detect/detect_openbsd.go

@@ -2,12 +2,18 @@
 
 package detect
 
+import (
+	"github.com/gogrlx/snack"
+	"github.com/gogrlx/snack/ports"
+)
+
 // candidates returns manager factories in probe order for OpenBSD.
-// TODO: wire up ports.New() once the ports package is implemented.
 func candidates() []managerFactory {
-	return nil
+	return []managerFactory{
+		func() snack.Manager { return ports.New() },
+	}
 }
 
 func allManagers() []managerFactory {
-	return nil
+	return candidates()
 }