updating the world-kit rules across protocol and ui

spoolcast used to have a "cast" step — pick the characters, move on. that was too narrow. a beat needs more than people: a locked style, an environment, props, an on-screen document, a camera move, sometimes a one-off reference that only matters for one shot. so cast became one subsection of a broader stage: world kit.

the protocol side moved first — world-kit.md is the source of truth now, cast.txt is demoted to just the recurring-character manifest. then the web ui had to match: the workflow graph shows world kit as step 05, between structure and screenplay, and clicking it opens a planning panel with every subsection. each reference carries a share scope — episode, show, or format template — and nothing implies a fixed "one character + one environment" recipe.

the part i had to correct: i first wired the "template" share scope to the visual style (wojak gpt-image) instead of the format template (the remotion-illustration pipeline). same word, two meanings. i added an AGENTS.md to the repo spelling out the difference — visual style vs format template, the episode < show < template scope ladder — so the next agent doesn't repeat it.