fix(submit): make replayed history deterministic

[ShivamB25]

Summary

• make replayed submission history deterministic instead of additive
• remove stale replayed days and recompute timestamp metadata correctly
• preserve untouched out-of-scope history while fixing in-scope replacements

Changes

• replace overlapping in-scope replay slices instead of stacking them
• remove omitted in-scope days from replay windows
• recompute or clear stale day-level earliest timestamps after replay changes
• lock the behavior with focused replay regression tests

Testing

• replay-focused Vitest coverage
• frontend typecheck
• frontend build
• local runtime replay validation against the app and Postgres

Depends on #443
Refs #441

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Project	Deployment	Actions	Updated (UTC)
tokscale	Ready	Preview, Comment	Apr 18, 2026 9:18pm

[ShivamB25]

This PR is intentionally stacked.

If it were marked as a standalone ready-to-merge change, reviewers would be looking at a diff that conceptually depends on code still under review in the earlier PR(s). Reviewing it in order keeps the trust-boundary changes, replay semantics, and public-surface changes easier to reason about.

[cubic-dev-ai]

1 issue found across 16 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="packages/frontend/src/lib/db/helpers.ts">

<violation number="1" location="packages/frontend/src/lib/db/helpers.ts:192">
P1: Incoming replay dates are not filtered by `replayWindow`, so out-of-scope days can still be inserted/updated if upstream input includes them.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: Incoming replay dates are not filtered by replayWindow, so out-of-scope days can still be inserted/updated if upstream input includes them.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At packages/frontend/src/lib/db/helpers.ts, line 192:

<comment>Incoming replay dates are not filtered by `replayWindow`, so out-of-scope days can still be inserted/updated if upstream input includes them.</comment>

<file context>
@@ -87,6 +148,132 @@ export function mergeClientBreakdowns(
+}: PlanSubmittedReplayArgs): PlannedReplayMutations {
+  const existingByDate = new Map(existingDays.map((day) => [day.date, day]));
+  const incomingByDate = new Map(incomingDays.map((day) => [day.date, day]));
+  const replayDates = new Set(incomingDays.map((day) => day.date));
+
+  for (const existingDay of existingDays) {
</file context>

Suggested change

	const replayDates = new Set(incomingDays.map((day) => day.date));
	const replayDates = new Set(
	incomingDays
	.filter((day) => isDateWithinReplayWindow(day.date, replayWindow))
	.map((day) => day.date)
	);