Mirrors Metrics.tsx's click-to-edit pattern: clicking a param chip populates the declaration form, shows an "Editing" indicator, and swaps the submit button for Save changes / Cancel. The name field is locked while editing since declare_param overwrites in place by name — renaming would silently orphan the original and anything referencing it. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01XFUNZwCvz3kcod3352ZR2o