Add Request Changes button to merge queue UI

[iamnbutler]

Summary

• Wires up the existing requestChanges() API function (api.ts:78-88) in the merge queue UI
• Adds a "Request Changes" button between Approve and Reject for pending entries in both the list view (page.tsx) and table view (columns.tsx)
• Opens a dialog to collect feedback, which is sent to the backend's /api/merge-queue/:id/request-changes endpoint
• The task is then re-dispatched with the reviewer's feedback

Test plan

• Navigate to the merge queue page with pending entries
• Verify "Request Changes" button appears between Approve and Reject
• Click "Request Changes" and verify the dialog opens
• Verify Submit is disabled when feedback is empty
• Enter feedback and submit — verify the entry transitions to changes_requested status
• Verify the feedback text appears as a subtitle on the entry row

Closes #520

🤖 Generated with Claude Code

[github-actions]

PR adds a Request Changes button with a feedback dialog to the merge queue UI — the core feature works correctly. One important issue and two suggestions.

Overview: The changes touch two views of the merge queue (table view in columns.tsx, list view in page.tsx). The table view correctly extracts a MergeActions component to hold dialog state; the list view duplicates the same logic inline instead of reusing it.

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[IMPORTANT] MergeActions.handleApprove / handleReject silently swallow errors — no toast.error on failure, unlike the equivalent handlers in page.tsx. Table-view users won't know if approve or reject failed. See inline comment on columns.tsx:144.

[SUGGESTION] requestChanges(id, rcFeedback.trim(), rcFeedback.trim()) passes the same value for both reasoning and feedback. These are distinct fields in the API — reasoning ends up in the event log, feedback is stored on the entry and sent to the agent. Either collapse them in the API or surface both in the UI. See columns.tsx:153.

[SUGGESTION] The Request Changes dialog state + handler is duplicated between MergeActions (columns.tsx) and MergeQueueRow (page.tsx). Exporting MergeActions and reusing it in the list view would eliminate the duplication. See page.tsx:94.

Reviewed by PR / Review

[github-actions]

[IMPORTANT] — Correctness

handleApprove and handleReject here have no try/catch. If the API call fails, the error is silently swallowed and the user sees no feedback. The equivalent handlers in page.tsx's MergeQueueRow both have toast.error(...) on failure — this component should too.

async function handleApprove() {
  try {
    await approveMerge(entryId);
    onRefresh();
  } catch {
    toast.error("Failed to approve merge entry");
  }
}

async function handleReject() {
  try {
    await rejectMerge(entryId);
    onRefresh();
  } catch {
    toast.error("Failed to reject merge entry");
  }
}

[github-actions]

[SUGGESTION] — Code Quality

reasoning and feedback are passed the same value. The API accepts two semantically distinct fields — reasoning ("why changes are needed", used in the event log for observability) and feedback ("specific actionable instructions for the agent", stored on the entry and re-dispatched). Passing the same string to both is harmless today, but it means the event log contains a duplicate. Worth either:

1. Collapsing the API to a single field if the distinction has no practical value, or
2. Surfacing a second field in the UI if the distinction matters.

Same pattern in page.tsx:114.

[github-actions]

[SUGGESTION] — Code Quality

This dialog logic (rcOpen, rcFeedback, rcSubmitting, handleRequestChanges, and the full Dialog JSX below) is identical to what was just extracted into MergeActions in columns.tsx. Rather than duplicating it inline here, MergeActions could be exported and reused:

// columns.tsx
export function MergeActions({ entryId, onRefresh }: { entryId: string; onRefresh: () => void }) { … }

// page.tsx (inside MergeQueueRow actions section)
(MergeActions entryId={entry.id} onRefresh={onRefresh} /)

Two copies means the next change to this dialog has to be made twice.

[iamnbutler]

Closing duplicate - newer PR #724 exists