Add a key-centered form editor view for locating and mapping fields

[prestoncabe]

Problem

In the form editor, it should be easy to locate the field associated with a given key and to identify keys that have not yet been mapped.

Proposed direction

Consider tabs in the left pane:

1. Components: the existing component view.
2. Keys: a new view centered on keys and their associated fields.

The Keys view could serve two functions:

• Replace the “Validate Form Outputs” drawer, visually differentiating mapped and unmapped keys (for example, with color coding).
• Streamline form development:
  • For unmapped keys, suggest a question name and component that can be associated with the key and added to the form. Explore whether AI would help with these suggestions.
  • For mapped keys, display the actual associated question/label. Clicking it should select the field in the form and open its details, just as manually selecting that field does.

The tabbed layout and AI suggestions are ideas to explore, rather than settled implementation requirements.

Related: #444, #61.