Add Draft with your agent: a diagram from words, drafted by any agent

[raj-khan]

FL-90, criterion 1 of 2.

• Draft with your agent (menu, command palette): describe a diagram in words, then copy the prompt or open it already filled in at Claude or ChatGPT. Paste the answer back; it is checked as you paste (line errors, or "4 shapes and 4 connections, ready") and Use this diagram draws it as one undoable change. isketch sends nothing anywhere.
• src/domain/draft.js: draftPrompt teaches the format (rules, every shape from the registry, a valid example) and asks for one fenced block; readDraft takes the first fenced block of an answer, or the whole answer.
• Tried on a real model: claude -p --model haiku with the prompt for a URL shortener returned valid .flow first time (8 shapes, 7 connections, every part named).

Criterion 2, a built-in version, is your call (asked on the task): the person's own API key in the browser (no cost to you), or a call through the isketch server with your key (simplest for them, costs you per diagram, needs rate limits).

Tests: draft.spec.js (6), e2e/draft.spec.js. vitest 311, e2e 145, lint and typecheck.