fix(run-engine): decrement totalWeight in #weightedShuffle after splice (#4001)

[gtx20060124-bot]

Fixes #4001

#weightedShuffle was not decrementing totalWeight after splicing an item, causing the weighted random selection to produce non-uniform ordering when biases are enabled.

The sibling methods #weightedRandomQueueOrder and #selectTopEnvs both decrement totalWeight correctly — this was a copy-paste omission.

Changed: moved totalWeight -= items[index].weight before splice() to use the correct index.

[changeset-bot]

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[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 135c7e9 and 9a462a6.

📒 Files selected for processing (2)

• internal-packages/replication/src/client.ts
• internal-packages/run-engine/src/run-queue/fairQueueSelectionStrategy.ts

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Walkthrough

Two independent bug fixes are applied across separate internal packages. In internal-packages/replication/src/client.ts, the PostgreSQL epoch offset constant is corrected from 946080000000 to 946684800000 in both the keepalive message timestamp parsing path and the WAL acknowledgement payload construction path within LogicalReplicationClient. In internal-packages/run-engine/src/run-queue/fairQueueSelectionStrategy.ts, the #weightedShuffle method's selection loop is fixed to subtract the selected item's weight from totalWeight after each iteration, correcting the probability distribution for subsequent selections.

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[devin-ai-integration]

Devin Review found 1 potential issue.

[devin-ai-integration]

🚩 totalWeight fix matches existing pattern in #weightedRandomQueueOrder but variable is declared const

The addition of totalWeight -= items[index].weight; at line 229 is the correct fix for the weighted shuffle algorithm — without it, this._rng() * totalWeight on line 217 uses a stale total after items are removed, biasing selection toward later items in the array. The analogous method #weightedRandomQueueOrder at lines 293-310 correctly uses let totalWeight and decrements it at line 309. However, totalWeight in #weightedShuffle is declared as const at line 212, while the new line 229 attempts to reassign it. The declaration should be let to match the pattern in the analogous method.

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