Tracked from v0.6.6 parallel stream: ui-redesign sub-agent failed with API parse error. Partial work on palette.rs and header.rs in worktree .worktrees/ui-redesign.

Remaining tasks from TODO_UI_DESIGN.md:

1. Tool cards (widgets/tool_card.rs) with rail/header/body/footer per family
2. Reasoning texture (dashed rail, italic body, warm bg tint)
3. Sub-agent in-transcript cards (widgets/agent_card.rs)
4. Bottom-strip consolidation (mode, model, time, tokens, cost on one line)
5. Wave glyphs replacing arc cups
6. Speaker glyphs (dot for assistant, bar for user)