Brief A — Prompt Composer (executed under Prompt 01, single-agent)

Success predicate written first, per the brief-template's ordering rule.

TASK (goal)
  Ship one self-contained interactive page at runs/composer.html that,
  in a browser, assembles a complete ARC(E)-structured marketing
  prompt from user inputs and emits it as copyable text — such that
  an automated browser check can fill the form, click Assemble, and
  find every assembled section (ROLE, ACTION, CONTEXT, EXPECTATION)
  plus optional brand-voice and quality-check blocks present in the
  output.

  OBLIGATION (exact)
  The page must: offer all 13 library sections as task categories;
  offer a role picker seeded with roles used by the library
  ("Act as a ..." lines); accept free-text objective, audience,
  specifics and length; include toggles for (a) brand voice block,
  (b) quality-check append, (c) long-horizon persistence block with
  its paired verification gate; render the assembled prompt live;
  and provide a Copy button that writes the prompt to the clipboard.

  NOT ALLOWED TO:
  - modify any existing site page, asset, or markdown source
  - add any dependency that does not ship inside the single file
    (no CDNs, no fonts, no external JS)
  - touch files outside prompts-site/runs/, prompts-site/build-site.sh
    (build wiring only), and this brief

  Assume a complete solution exists and is reachable with the tools
  available to you.

DOES NOT COUNT
  - a page that renders but whose Assemble output omits any
    assembled section (the automated check must find them all)
  - inline JS that fails `node --check`
  - an HTML document whose tags do not balance under a strict parse
  - a plan to build the composer, or a description of its UI
  - wiring the page into the build while the build fails
  - reporting the browser behavioral check without having run it in
    a real browser session and read its actual output
  - silently reducing the category list below 13, the toggles below
    3, or dropping the Copy button

DEFINITION OF DONE (each backed by a command result in this session)
  1. `node --check` on the extracted inline JS returns 0
  2. strict HTML parse (python html.parser, tag balance) exits 0
  3. `./build-site.sh` exits 0 and reports page count >= 16
  4. deployed: `curl` of https://prompts.mikee.pro/runs/composer.html
     returns 200 with size > 10000 bytes
  5. behavioral check in a real browser: form filled, Assemble
     clicked, output contains all 4 ARC(E) sections, at least one
     selected role string, and the QA text when its toggle is on
  6. every numbered plan item marked done by number ("N of M done")

EFFORT
  Attempt at least three distinct approaches before reporting any
  check as blocked; state what each attempt returned.