Phase 1 — group ride creation (no phantom rides):
- Check authentication and Firestore availability BEFORE touching UI state; an unauthenticated
user (or unavailable Firestore) now gets an actionable error and no phantom ride, instead of a
local entry that was never saved.
- Insert the ride into UI state ONLY after batch.commit() confirms the write; on commit failure
nothing is inserted and an error is shown.
- Prevent duplicate submissions: the create modal disables its submit button while in flight, and
the hub guards with a ref.
- The join code remains the real Firestore document id (no fabricated ids).
- Extract commitGroupRide (pure, dependency-injected) so every path is unit-testable.
Phase 2 — replay playback timing:
- The elapsed clock and rider marker both derive from the same cursor, so they cannot drift.
- Manual seeks (scrub, restart, corner jump, arrow keys) go through seekTo(), which reconciles
playback timing (clears carry/last-frame) so no stale budget is applied after a seek.
- Make gap compression explicit: a caption labels the timeline as recorded elapsed time and warns
that dead time in multi-segment recordings is skipped during playback.
Tests: commitGroupRide (unauthenticated / unavailable / commit-ok / commit-failed); group-rides
hub now uses an authenticated mock with deterministic Firebase — authenticated create persists,
unauthenticated create is blocked with no phantom, a failed commit leaves no phantom, and the
create modal blocks duplicate submits.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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