[Leftium]

Refs #62, PR 3. Builds on merged #63 and #64. Keep #62 open for Clip-settings PR 4; watch reveal/docking remains #15. Do not merge as part of this task.

This PR follows the Continuum protocol at 9aea333.

Summary

Prev Frame and Next Frame now pause and request one nominal time step on a tap, or repeat while held. Repeat begins after 350 ms and runs every 200 ms. Releasing stops repeat without another step and leaves playback paused. Both directions honor A/B in Clip Only and source limits in VIDEO. Loop wraps across those limits; Once stops at them.

Previously each step read a provider timestamp that could lag behind the last request. The new stepper accumulates integer quanta from a fractional logical anchor, so late or quantized YouTube observations cannot overwrite the logical stepping position. Provider seeks run at most once per 200 ms; rapid taps replace one pending target instead of accumulating commands. The final queued target is sent within that interval, and other navigation discards it.

Changes

• Share one pointer/keyboard repeat owner across both buttons. Handle outside release, pointer cancellation, lost capture, secondary touch, blur, visibility changes, history/source changes, disabled controls, other interactions, and component cleanup. Prevent native release-click and keyboard-repeat double stepping; preserve ordinary assistive-technology activation.
• Honor the selected playback scope and Loop/Once in both directions. In Clip Only, Loop wraps Next past B to A and Prev before A to B; Once clamps and stops at A/B. VIDEO uses the same policy at the source limits. Taps and holds preserve bounds, URLs, Loop/Once, and scope. Switching scope cancels repeat and pending frame seeks. Timeline/video scrubbing can still inspect outside A:B; Play re-enters the clip when necessary.
• Preserve the existing player/iframe, provider focus handling, video gestures, timeline geometry, endpoint preview and A/B swap behavior.
• Document the nominal 30 fps default and provider limits. The pure helper accepts alternative supplied quanta, including 24/25/29.97/60 fps; no FPS inference or selector was added. YouTube and Video.js document time seeks without an exact-frame operation. Requested time is not a decoded-frame acknowledgement, and visible frames may repeat or skip.

Verification

The GitHub verification run passed for f4abfbf, including production-mode hosting/social checks and the routine browser gate. Vercel deployed successfully.

Local checks:

• pnpm check: no errors or warnings.
• pnpm lint and pnpm build: passed.
• pnpm test:clip: 30 passed, including seven new fake-timer/math checks covering both A/B edges, Loop wrapping, Once stopping, reversal, outside-clip positions and scope resets.
• pnpm test:share-url: 24 passed; pnpm test:metadata: 18 passed.
• pnpm test:browser:frames: 4 passed across Chromium/WebKit, with external requests blocked. Covers mobile-width mouse/touch/keyboard/AT activation, delay/cadence, stale observations, release/cancel, history/source change, teardown, both-direction A/B tap/hold wrapping in Loop and stopping in Once, whole-source limits in VIDEO, scope-switch cleanup, Clip Only re-entry, unchanged bounds/URL and provider identity.
• pnpm test:browser:timeline: 8 passed across Chromium/WebKit on the previous implementation revision; timeline/scrub behavior is unchanged by the scope update.
• pnpm test:browser: 36 passed, unchanged gate membership.

Test lifecycle: the seven cheap Node checks remain permanent because stale-provider accumulation, repeat ownership and cancellation are recurring transport risks. The two new browser cases are probationary through Clip-settings PR 4 in #62 and excluded from routine gates. Reviewed all four existing timeline cases: capture/swap, keyboard restoration and editor/watch scrub cleanup still cover distinct browser contracts, so retain them through the same PR 4 review point. No existing test became obsolete, and routine gate membership is unchanged. Broader live-provider/advisory coverage was not run.

Follow-ups

Physical iPhone Safari/Android and real YouTube stepping latency remain pending manual verification, especially in unbuffered regions and long videos. Mocked WebKit verifies application and adapter behavior, not decoded-frame accuracy or physical-device compatibility.

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Project	Deployment	Actions	Updated
youloop	Ready	Preview	Oct 14, 2026 9:24pm UTC

[Leftium]

This PR was claimed

[Leftium]

This PR's claim 6178425919 was released at 0de9c1c

[Leftium]

This PR was claimed

[Leftium]

This PR's claim 6178736719 was released at f4abfbf