feat(tui): set up cloud while the model downloads, and see the pull anywhere

[plombeer31]

Stacked on #226 → #225 → #224 → #223 → #222 → #220.

Why

A local first run leaves the operator in front of a 2.7–22 GB progress bar with nothing to do, and a cloud model takes about a minute to configure. The pull is owned by a session-scoped orchestrator — it does not need the screen that started it — but it was only ever drawn inside the LLM panel, so walking away from that tab meant a multi-gigabyte transfer running with nothing anywhere saying so.

Three changes

The offer. The download screen carries an accent-marked block:

  ┃  Don't want to wait? Set up a cloud model in the meantime —
  ┃  it takes about a minute, and the download keeps running.    press c

Hidden when a cloud provider is already configured — nothing left to offer.

Wait or jump. Finishing that wizard while the pull is still running asks the only question left:

  ✓  Cloud model ready
  ⇣  gemma-4-e4b · 61% · 2.6 GB / 4.2 GB · about 2 minutes left

  ›  Start using the agent now
     the download keeps running; progress shows in the top bar

     Wait here until it finishes
     the agent opens with both backends live

Jumping is the default row — waiting is a preference, not a requirement. If the pull already landed by the time the wizard closes, the flow finishes instead of asking a question with one answer. Backing out of the wizard returns to the download, not to a backend choice that has already been made.

The chip. DownloadChip renders the pull in the status bar — model, bar, percent, ETA — for as long as one is running, from any screen:

   R U N    ⇣ gemma-4-e4b ███████░░░ 61%  about 2 minutes left

Notes for review

• resumeAfterCloud on the flow state is what distinguishes "cloud wizard from the choice screen" (finish) from "cloud wizard from a running download" (ask). It is cleared on both exits.
• The reducer decides wait-vs-finish from localModelsPanel.pull !== null — state, not config, so it stays pure.
• The embedding-offer suppression now covers the whole local branch including the cloud detour, rather than only the download step.
• use-typewriter.test.tsx got a longer poll deadline: it waits on Ink frame commits, which slow down considerably under a full parallel run.

Tests

Five reducer cases (open-with-memory, wait-or-jump on a live pull, finish when it already landed, back-out to the download, pull landing while wait-or-jump is up), plus download-chip.test.tsx — one-row chip, runtime naming, both rows of wait-or-jump and its default cursor.

Full suite: 5205 passed; the two long-standing failures are unchanged on main.