Import Frame: turn unstructured context into a structured Frame with an LLM

Motivation

Two pieces of feedback point the same direction:

• Authoring a Frame through the full typed form is overwhelming.
• Orgs already have the context written up elsewhere (e.g. Google Docs) in prose that isn't in the Frame format.

We want a low-friction path: bring existing prose in, let an LLM map it into the Frame schema, review it, and create the Frame. This lowers the barrier for non-technical authors and makes it easy to migrate context that already exists.

Proposal (surface - do one or both; web is the priority)

• Web import flow (priority): in the web app, paste or upload the source text. A "draft with AI" step produces structured slots, which pre-fill the authoring form for the user to review and adjust before publishing. This targets the "form is overwhelming" feedback head-on. Needs a decision on where the LLM call runs (backend with a configured provider/key vs client-side).
• MCP-driven import: the connected AI client (e.g. Claude) reads the source doc and calls create_frame (#51) with structured slots. No new LLM infrastructure in Frames; the client's model does the structuring. Good for users already wired to the MCP endpoint.

Guardrails

• LLM output must validate against the fixed Frame schema (unknown keys rejected).
• Always show a review/confirm step before anything is created. Never auto-publish unreviewed LLM output.
• Map only what is confidently present; leave slots empty rather than inventing content.

Dependencies

• MCP path depends on #51 (create_frame).
• Web path can reuse the existing PublishFrame RPC.

Acceptance criteria

• A user can go from a blob of unstructured context to a reviewed, schema-valid Frame without hand-filling every slot.
• The drafted Frame is presented for review/edit before creation.
• Output always validates against the schema; low-confidence slots are left empty, not fabricated.

Start by comparing the proposed web flow with the MCP path, then inspect the existing PublishFrame RPC, the fixed Frame schema, and issue #51's create_frame dependency. Done means unstructured input produces a schema-valid draft that users can review and edit before creation, with uncertain slots left empty.