Unify expand and collapse timing

[MaggieAppleton]

Why

Revealing more content moved at four speeds on two curves: the sidebar 250ms, the research fold 420ms rows + 300ms opacity after a 120ms delay (about 540ms in all, the slowest motion in the app), the decision fold 200ms on --ease-out, and Chat tool-call details not at all (display: none).

What changed

• One preset: --acc-expand 250ms open, --acc-collapse 200ms close, --motion-move. --acc-collapse goes from 250ms to 200ms, and the collapse contract's closeDuration follows (200).
• Research fold and decision fold use those tokens (open = expand, close = collapse); the 120ms delay and the bespoke 420/300ms values are gone, with their preserved-values.json exception.
• Chat tool-call details now use MotionDisclosure with the collapse contract, so they animate like the sidebar (previously instant).
• Reduced motion is unchanged: .motion-collapse and the folds still settle with transition: none.
• Not done: decision "Add an option" row swap (an input/focus swap in packages/question, not a fold) and the broader token cleanup (finding 9). Left closeDuration untouched in other contracts to avoid Keep workspace chrome still when switching documents #346.

Screenshots

Timing, not layout, changed. Height/opacity frame sequences every 50ms (before: main at :8795, after: this branch at :8864). The research, decision and tool-details folds were sampled by mounting the shipped classes in the live page, because the fake server has no Planner/research; the sidebar disclosure is the real component.

• Before: frames-before.txt (not committed), after: frames-after.txt.
• Settle time before to after: research open 533 to 260ms, research close 416 to 202ms, decision fold 199 to 259ms open / 210ms close, tool details instant to 258ms open / 208ms close, sidebar 253/324 to 243/246ms.

Testing

• bun run ci passes; bun run types passes.
• bun test apps/web packages/editor packages/question: all pass; tokens.test.ts timed out under machine load, passes alone with --timeout 60000.
• Local e2e suspended per the brief; relying on PR CI.

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