Fix task ordering in replay when participants use previous buttons

[jaykim1213]

In Participant View replay timelines, task ordering can become incorrect when a participant navigates backward using the previous button.

The startTime / endTime values can affect the replay timeline ordering and make tasks appear out of sequence. They should always show up in the their sequence order

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Specification

Added after specification review.

Summary

Participant View replay timelines should render tasks in study sequence order even when a participant used Previous and the saved startTime / endTime values are no longer monotonic. This should be a replay rendering fix, not a stored-data migration.

Decisions

• Sort replay task entries by parsed trialOrder, using sequence step first, dynamic funcIndex second, and task identifier as a stable tie-breaker.
• Keep startTime / endTime as the source for timeline scale, task bar position, bar width, duration, and browsed-away overlays.
• Include incomplete answers with startTime === 0 in the same sequence-order sort rather than appending them after completed tasks.
• Sort dynamic block trials such as 3_0, 3_1, and 3_2 by parent step and then funcIndex; if both a non-dynamic 3 and dynamic children exist, the non-dynamic step sorts before its dynamic children.
• Do not modify saved participant answer data.
• Do not change analytics summaries or exported data ordering unless they share the same visible Participant View replay timeline bug.

Acceptance Criteria

• Participant View replay timeline renders task labels/tasks in study sequence order when saved answers have non-monotonic startTime values caused by Previous navigation.
• Dynamic/repeated task answers sort by trialOrder step and funcIndex.
• Incomplete answers do not get appended out of sequence solely because startTime === 0.
• Timestamp-based bar scale, bar widths, and browsed-away overlays continue to use recorded startTime / endTime.
• Clicking a task in the replay timeline still opens the correct trial using that task's trialOrder.
• Focused unit coverage is added for the ordering helper or AllTasksTimeline behavior using out-of-order timestamps.

Out of Scope

• Rewriting participant answer persistence.
• Changing how startTime / endTime are collected.
• Changing exported analytics semantics.
• Adding new libraries.

Implementation Notes

• The likely control point is src/analysis/individualStudy/replay/AllTasksTimeline.tsx, which currently sorts completed tasks by startTime while incomplete tasks use trialOrder.
• Prefer reusing the existing parseTrialOrder utility instead of adding ad-hoc parsing logic.
• Existing think-aloud replay code already orders answers by parsed trialOrder with an identifier tie-breaker; use that as the behavioral reference.

Testing Notes

• Add a focused Vitest test for out-of-order timestamps where trialOrder is still ordered, including at least one dynamic trialOrder case.
• Confirm timestamp-driven visual metrics still use startTime / endTime after the ordering change.