[samuel-williams-shopify]

Reset was always available and treated the first slide specially. Reset is now available only while paused and always uses the current slide's expected timestamp. Ordinary slides stay paused; timer: start slides return to the ready state at that timestamp, so advancing starts from the correct position even midway through the deck.

• Show Start, Pause, or Resume + Reset according to the timer state. Waiting slides show a gently pulsing Auto-start indicator, with a reduced-motion fallback.
• Explain outgoing timer actions in the Next tooltip and preserve keyboard focus by leaving unchanged paused controls in place.
• Make Clock#reset! / reset!(nil) clear the clock, replacing stop!. Numeric resets preserve whether it is running and move a ready clock into the paused state; started: false prepares a timestamp for a later start.
• Preserve the ready clock's timestamp when saving/restoring, and account for it in the remaining-time display.
• Add a zero-duration waiting slide without speaker notes and update the guides, release notes, and regression tests.

Validation: 305 Ruby tests (736 assertions), 100% line coverage, 31 JavaScript tests, RuboCop, documentation coverage (185/185), and static package checks. Chrome checks confirmed the Auto-start animation and reduced-motion fallback.