docs: record the conversation chrome and mark decisions as stages 34 and 10

[benjipeng]

What

Design decisions the owner made on rendered candidates, recorded in the documents that own them. No code changes.

• ui-ux: the activity line moves while the agent works — the mark's core, the label, elapsed time, effort, and how long the route has been quiet — on the visible-only clock the effort rail already owns, replacing "owns no animation clock". The user's message sits on a band of lifted ground behind a blue › instead of the accent bar. An empty conversation shows the mark.
• Phase 04: stage 10 branding rewritten to the decided mark; new stage 34, conversation chrome. Both planned and unstarted.
• Plans for stages 34 and 10, carrying MOT-1 to MOT-3 inline until code cites them.
• Spike conversation-chrome: what was shown, what the owner chose and rejected, the cell measured for two fonts, the Material Design glyphs used, and a source survey of Claude Code, Codex and Grok. The mockup generators are kept beside it and write their pages to the system temporary directory, outside the corpus.

Open

Which glyph set draws the activity mark — Unicode geometric shapes or the Nerd Font's Material Design outlines — and at what length. The owner decides once their terminal font settles; it blocks only stage 34's third slice.

Verified

Local: citations, file length, crate graph, frames, fmt and typos pass. The doc budget is advisory: ui-ux.md grows to 7.7 KB over its budget. CI not yet observed.