#22340 Agent chat: running spinner turns; turn footer sits on the answer's side

Leo (2026-10-19, nightly): the Running spinner does not animate, and "Worked for 2s · 4:44 PM" sits on the right under the user's bubble.

• Spinner (icons.tsx) now carries .cv-spinner, which rotates (900ms linear), and holds still under Reduce Motion and the Static status indicators.
• .cv-turn-actions is left-aligned with the answer's text.

Tests (committed first): test/agent-pane-turn-rows-motion-side.test.ts, real Chromium and WebKit against the pane's dev entry and a stand-in acpmux. On the base the ring's angle never changes and the footer starts 517px right of the answer. static-status-loops now also covers the ring.
Not included: the optional reverse-sides setting (low priority, not started).
Risk tier: low (CSS and one className).

🤖 Generated with Claude Code

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Summary by cubic

Fixes two agent-chat papercuts: the running spinner never animated, and the turn footer ("Worked for 2s · 4:44 PM") sat at the column's right edge under the user's bubble.

• The Spinner icon now rotates via .cv-spinner (900ms linear), holding still under Reduce Motion and Static status indicators.
• The .cv-turn-actions footer now starts at the answer's left edge; the Debug "Turn footer actions" choice defaults to Left, with its Right option moving it back (the webview now applies this setting).

Added browser tests against the pane's dev entry with a stand-in acpmux, and extended static-status-loops coverage.