fix: skip agent spawn on zero-conflict merges; carry prior review context across passes

- resolveConflictsSession: guard against reattemptMerge returning
  clean=false with zero unmerged paths (branch already merged, dirty
  index, stale ref). Previously fell through to spawning a full agent
  session with no conflicts to resolve. Now tries completeMerge or
  aborts without spawning.

- Review-gated loop: accumulate rejected reviews in a priorReviews
  array and inject them into buildReviewPrompt via a new
  ReviewPromptOptions.priorReviews field. The reviewer now sees prior
  findings and can verify they were addressed instead of re-reviewing
  from scratch each pass. Added renderPriorReviews() helper and wired
  it into both buildReviewPrompt and buildReviewPromptUncommitted.

src/executor.ts

@@ -936,6 +936,10 @@ async function executeTask(
 						// A FAILED range computation (broken/stale base ref, git error) is
 						// logged as a distinct warning and is never treated as a clean,
 						// verified task — only a GENUINE "no changes" skips review.
+						// Accumulated rejected reviews from earlier passes — injected
+						// into the next review prompt so the reviewer sees prior
+						// findings and can verify they were addressed.
+						const priorReviews: ReviewResult[] = [];
 						while (true) {
 							if (!baseRef) {
 								sendChatMessage?.(
@@ -976,6 +980,7 @@ async function executeTask(
 							{
 								projectContext: config.prompts.projectContext,
 								focus: config.prompts.reviewFocus,
+								priorReviews,
 								diffOptions: {
 									extraPatterns: compileIgnorePatterns(
 										config.review.extraIgnorePatterns,
@@ -1097,6 +1102,9 @@ async function executeTask(
 								break; // changes already committed — merge proceeds
 							}
 
+							// Accumulate the rejected review so the next review pass
+							// sees prior findings and can verify they were addressed.
+							if (review) priorReviews.push(review);
 							attempt++;
 							reviewRetries++;
 							sendChatMessage?.(
@@ -1779,6 +1787,52 @@ async function resolveConflictsSession(
 		return;
 	}
 
+	// Merge failed but produced no unmerged paths — no real conflicts to
+	// resolve. This can happen when the branch tip was already merged by the
+	// first attempt (mergeWorktree) before it aborted, or when the merge
+	// fails for a non-conflict reason (dirty index, stale ref). Don't spawn
+	// an agent session for zero conflicts — abort or complete and finish.
+	if (attempt.conflicts.length === 0) {
+		// Try to complete whatever merge state exists; if there's nothing to
+		// commit, abort to leave the working tree clean.
+		if (completeMerge(projectDir)) {
+			sendChatMessage?.(
+				`✓ conflicts auto-resolved for ${task.id} · ${task.title}`,
+			);
+			removeWorktree(projectDir, worktree);
+			progress.markCompleted(
+				task.id,
+				0,
+				undefined,
+				undefined,
+				undefined,
+				[],
+				"",
+				undefined,
+				0,
+			);
+			try {
+				updateTaskInFile(project.sourcePath, task.id, "completed");
+			} catch {
+				// Best-effort
+			}
+			return;
+		}
+		abortMerge(projectDir);
+		sendChatMessage?.(
+			`~ conflict resolution for ${task.id} · ${task.title} — merge produced no conflicts but could not be completed`,
+		);
+		progress.markFailed(
+			task.id,
+			`Merge of ${branch} produced no conflicts but could not be completed`,
+		);
+		try {
+			updateTaskInFile(project.sourcePath, task.id, "failed");
+		} catch {
+			// Best-effort
+		}
+		return;
+	}
 	// Conflicts exist — spawn a resolution agent session.
 	const prompt = buildConflictResolutionPrompt(
 		task,

src/prompts.ts

@@ -29,6 +29,12 @@ export interface ReviewPromptOptions {
 	focus?: string;
 	/** Noise-filter overrides (config.review.*). */
 	diffOptions?: DiffOptions;
+	/** Prior review results from earlier passes in a review-gated loop.
+	 *  Each rejected review is injected into the next review prompt so the
+	 *  reviewer can verify prior findings were addressed and catch new
+	 *  regressions introduced by the fix attempt — instead of re-reviewing
+	 *  from scratch. */
+	priorReviews?: ReviewResult[];
 }
 
 // ─── Task Prompt ─────────────────────────────────────────────────────────────
@@ -258,8 +264,12 @@ export function buildReviewPrompt(
 	parts.push(renderDiffSection(summary, filtered, "### Diff"));
 	parts.push("");
 
-	// ── Custom Review Focus ──
+	// ── Prior Review History (review-gated re-review) ──
 
+	parts.push(renderPriorReviews(opts.priorReviews ?? []));
+	if (opts.priorReviews && opts.priorReviews.length > 0) parts.push("");
+
+	// ── Custom Review Focus ──
 	if (opts.focus) {
 		parts.push("## Custom Review Focus");
 		parts.push(opts.focus);
@@ -360,7 +370,11 @@ export function buildReviewPromptUncommitted(
 	parts.push(
 		renderDiffSection(summary, filtered, "### Current Tracked Diff (git diff)"),
 	);
-	parts.push("");
+
+	// ── Prior Review History (review-gated re-review) ──
+
+	parts.push(renderPriorReviews(opts.priorReviews ?? []));
+	if (opts.priorReviews && opts.priorReviews.length > 0) parts.push("");
 
 	// ── Custom Review Focus ──
 
@@ -469,6 +483,45 @@ function renderDiffSection(
 	return lines.join("\n");
 }
 
+/**
+ * Render a "Prior Review History" section from earlier rejected reviews.
+ * Returns an empty string when there are no prior reviews so callers omit
+ * the section entirely.
+ *
+ * Each prior review's verdict, summary, and findings are listed so the
+ * reviewer can verify the developer addressed them and watch for new
+ * regressions — instead of re-reviewing from scratch on each pass.
+ */
+function renderPriorReviews(priorReviews: ReviewResult[]): string {
+	if (priorReviews.length === 0) return "";
+	const lines: string[] = [];
+	lines.push("## Prior Review History");
+	lines.push(
+		"Previous review pass(es) rejected this task. Verify each finding was",
+		"addressed in the current diff and watch for new regressions:",
+	);
+	lines.push("");
+	for (let i = 0; i < priorReviews.length; i++) {
+		const r = priorReviews[i];
+		if (!r) continue;
+		lines.push(`### Review ${i + 1} — ${r.verdict.toUpperCase()}`);
+		lines.push(`Summary: ${r.summary}`);
+		if (r.findings.length > 0) {
+			lines.push("Findings:");
+			for (const f of r.findings) {
+				const loc = f.file
+					? f.line
+						? ` (${f.file}:${f.line})`
+						: ` (${f.file})`
+					: "";
+				lines.push(`- [${f.severity}]${loc} ${f.message}`);
+			}
+		}
+		lines.push("");
+	}
+	return lines.join("\n");
+}
+
 function reviewInstructions(): string[] {
 	return [
 		"- **Correctness**: Does the implementation fulfill the task requirements?",