fix: address code review feedback - retry logic and import order

- Add retry logic with exponential backoff for stats DB insertions
  (100ms, 200ms, 400ms delays, max 3 attempts)
- Fix import order in types.ts (move constant after imports)
- Update stats-listener tests for async retry behavior
- Add new test for retry success on transient failure

Addresses review recommendations:
- High: Stats database error handling with retry logic
- Low: Import order consistency

src/main/process-listeners/__tests__/stats-listener.test.ts

@@ -32,7 +32,7 @@ describe('Stats Listener', () => {
 
 		mockStatsDB = {
 			isReady: vi.fn(() => true),
-			insertQueryEvent: vi.fn(() => 1),
+			insertQueryEvent: vi.fn(() => 'event-id-123'),
 		} as unknown as StatsDB;
 
 		mockProcessManager = {
@@ -52,7 +52,7 @@ describe('Stats Listener', () => {
 		expect(mockProcessManager.on).toHaveBeenCalledWith('query-complete', expect.any(Function));
 	});
 
-	it('should record query event to stats database when ready', () => {
+	it('should record query event to stats database when ready', async () => {
 		setupStatsListener(mockProcessManager, {
 			safeSend: mockSafeSend,
 			getStatsDB: () => mockStatsDB,
@@ -73,17 +73,20 @@ describe('Stats Listener', () => {
 
 		handler?.(testSessionId, testQueryData);
 
-		expect(mockStatsDB.isReady).toHaveBeenCalled();
-		expect(mockStatsDB.insertQueryEvent).toHaveBeenCalledWith({
-			sessionId: testQueryData.sessionId,
-			agentType: testQueryData.agentType,
-			source: testQueryData.source,
-			startTime: testQueryData.startTime,
-			duration: testQueryData.duration,
-			projectPath: testQueryData.projectPath,
-			tabId: testQueryData.tabId,
+		// Wait for async processing
+		await vi.waitFor(() => {
+			expect(mockStatsDB.isReady).toHaveBeenCalled();
+			expect(mockStatsDB.insertQueryEvent).toHaveBeenCalledWith({
+				sessionId: testQueryData.sessionId,
+				agentType: testQueryData.agentType,
+				source: testQueryData.source,
+				startTime: testQueryData.startTime,
+				duration: testQueryData.duration,
+				projectPath: testQueryData.projectPath,
+				tabId: testQueryData.tabId,
+			});
+			expect(mockSafeSend).toHaveBeenCalledWith('stats:updated');
 		});
-		expect(mockSafeSend).toHaveBeenCalledWith('stats:updated');
 	});
 
 	it('should not record event when stats database is not ready', () => {
@@ -113,7 +116,7 @@ describe('Stats Listener', () => {
 		expect(mockSafeSend).not.toHaveBeenCalled();
 	});
 
-	it('should log error when recording fails', () => {
+	it('should log error when recording fails after retries', async () => {
 		vi.mocked(mockStatsDB.insertQueryEvent).mockImplementation(() => {
 			throw new Error('Database error');
 		});
@@ -137,16 +140,26 @@ describe('Stats Listener', () => {
 
 		handler?.('session-789', testQueryData);
 
-		expect(mockLogger.error).toHaveBeenCalledWith(
-			expect.stringContaining('Failed to record query event'),
-			'[Stats]',
-			expect.objectContaining({
-				sessionId: 'session-789',
-			})
+		// Wait for all retries to complete (100ms + 200ms + final attempt)
+		await vi.waitFor(
+			() => {
+				expect(mockLogger.error).toHaveBeenCalledWith(
+					expect.stringContaining('Failed to record query event after 3 attempts'),
+					'[Stats]',
+					expect.objectContaining({
+						sessionId: 'session-789',
+					})
+				);
+			},
+			{ timeout: 1000 }
 		);
+		// Should have tried 3 times
+		expect(mockStatsDB.insertQueryEvent).toHaveBeenCalledTimes(3);
+		// Should not have broadcasted update on failure
+		expect(mockSafeSend).not.toHaveBeenCalled();
 	});
 
-	it('should log debug info when recording succeeds', () => {
+	it('should log debug info when recording succeeds', async () => {
 		setupStatsListener(mockProcessManager, {
 			safeSend: mockSafeSend,
 			getStatsDB: () => mockStatsDB,
@@ -166,15 +179,61 @@ describe('Stats Listener', () => {
 
 		handler?.('session-abc', testQueryData);
 
-		expect(mockLogger.debug).toHaveBeenCalledWith(
-			expect.stringContaining('Recorded query event'),
-			'[Stats]',
-			expect.objectContaining({
-				sessionId: 'session-abc',
-				agentType: 'claude-code',
-				source: 'user',
-				duration: 3000,
+		// Wait for async processing
+		await vi.waitFor(() => {
+			expect(mockLogger.debug).toHaveBeenCalledWith(
+				expect.stringContaining('Recorded query event'),
+				'[Stats]',
+				expect.objectContaining({
+					sessionId: 'session-abc',
+					agentType: 'claude-code',
+					source: 'user',
+					duration: 3000,
+				})
+			);
+		});
+	});
+
+	it('should retry on transient failure and succeed', async () => {
+		// First call fails, second succeeds
+		vi.mocked(mockStatsDB.insertQueryEvent)
+			.mockImplementationOnce(() => {
+				throw new Error('Transient error');
 			})
+			.mockImplementationOnce(() => 'event-id-456');
+
+		setupStatsListener(mockProcessManager, {
+			safeSend: mockSafeSend,
+			getStatsDB: () => mockStatsDB,
+			logger: mockLogger,
+		});
+
+		const handler = eventHandlers.get('query-complete');
+		const testQueryData: QueryCompleteData = {
+			sessionId: 'session-retry',
+			agentType: 'claude-code',
+			source: 'user',
+			startTime: Date.now(),
+			duration: 1000,
+			projectPath: '/test/project',
+			tabId: 'tab-retry',
+		};
+
+		handler?.('session-retry', testQueryData);
+
+		// Wait for retry to complete
+		await vi.waitFor(
+			() => {
+				expect(mockStatsDB.insertQueryEvent).toHaveBeenCalledTimes(2);
+				expect(mockSafeSend).toHaveBeenCalledWith('stats:updated');
+			},
+			{ timeout: 500 }
+		);
+		// Should have logged warning for first failure
+		expect(mockLogger.warn).toHaveBeenCalledWith(
+			expect.stringContaining('Stats DB insert failed'),
+			'[Stats]',
+			expect.any(Object)
 		);
 	});
 });

src/main/process-listeners/stats-listener.ts

@@ -7,9 +7,70 @@ import type { ProcessManager } from '../process-manager';
 import type { QueryCompleteData } from '../process-manager/types';
 import type { ProcessListenerDependencies } from './types';
 
+/**
+ * Maximum number of retry attempts for transient database failures.
+ */
+const MAX_RETRY_ATTEMPTS = 3;
+
+/**
+ * Base delay in milliseconds for exponential backoff (doubles each retry).
+ */
+const RETRY_BASE_DELAY_MS = 100;
+
+/**
+ * Attempts to insert a query event with retry logic for transient failures.
+ * Uses exponential backoff: 100ms, 200ms, 400ms delays between retries.
+ */
+async function insertQueryEventWithRetry(
+	db: ReturnType<ProcessListenerDependencies['getStatsDB']>,
+	queryData: QueryCompleteData,
+	logger: ProcessListenerDependencies['logger']
+): Promise<string | null> {
+	for (let attempt = 1; attempt <= MAX_RETRY_ATTEMPTS; attempt++) {
+		try {
+			const id = db.insertQueryEvent({
+				sessionId: queryData.sessionId,
+				agentType: queryData.agentType,
+				source: queryData.source,
+				startTime: queryData.startTime,
+				duration: queryData.duration,
+				projectPath: queryData.projectPath,
+				tabId: queryData.tabId,
+			});
+			return id;
+		} catch (error) {
+			const isLastAttempt = attempt === MAX_RETRY_ATTEMPTS;
+
+			if (isLastAttempt) {
+				logger.error(
+					`Failed to record query event after ${MAX_RETRY_ATTEMPTS} attempts`,
+					'[Stats]',
+					{
+						error: String(error),
+						sessionId: queryData.sessionId,
+					}
+				);
+			} else {
+				const delay = RETRY_BASE_DELAY_MS * Math.pow(2, attempt - 1);
+				logger.warn(
+					`Stats DB insert failed (attempt ${attempt}/${MAX_RETRY_ATTEMPTS}), retrying in ${delay}ms`,
+					'[Stats]',
+					{
+						error: String(error),
+						sessionId: queryData.sessionId,
+					}
+				);
+				await new Promise((resolve) => setTimeout(resolve, delay));
+			}
+		}
+	}
+
+	return null;
+}
+
 /**
  * Sets up the query-complete listener for stats tracking.
- * Records AI query events to the stats database.
+ * Records AI query events to the stats database with retry logic for transient failures.
  */
 export function setupStatsListener(
 	processManager: ProcessManager,
@@ -20,18 +81,16 @@ export function setupStatsListener(
 	// Handle query-complete events for stats tracking
 	// This is emitted when a batch mode AI query completes (user or auto)
 	processManager.on('query-complete', (_sessionId: string, queryData: QueryCompleteData) => {
-		try {
-			const db = getStatsDB();
-			if (db.isReady()) {
-				const id = db.insertQueryEvent({
-					sessionId: queryData.sessionId,
-					agentType: queryData.agentType,
-					source: queryData.source,
-					startTime: queryData.startTime,
-					duration: queryData.duration,
-					projectPath: queryData.projectPath,
-					tabId: queryData.tabId,
-				});
+		const db = getStatsDB();
+		if (!db.isReady()) {
+			return;
+		}
+
+		// Use async IIFE to handle retry logic without blocking
+		void (async () => {
+			const id = await insertQueryEventWithRetry(db, queryData, logger);
+
+			if (id !== null) {
 				logger.debug(`Recorded query event: ${id}`, '[Stats]', {
 					sessionId: queryData.sessionId,
 					agentType: queryData.agentType,
@@ -41,10 +100,6 @@ export function setupStatsListener(
 				// Broadcast stats update to renderer for real-time dashboard refresh
 				safeSend('stats:updated');
 			}
-		} catch (error) {
-			logger.error(`Failed to record query event: ${error}`, '[Stats]', {
-				sessionId: queryData.sessionId,
-			});
-		}
+		})();
 	});
 }

src/main/process-listeners/types.ts

@@ -4,6 +4,13 @@
  */
 
 import type { ProcessManager } from '../process-manager';
+import type { WebServer } from '../web-server';
+import type { AgentDetector } from '../agent-detector';
+import type { SafeSendFn } from '../utils/safe-send';
+import type { StatsDB } from '../stats-db';
+import type { GroupChat, GroupChatParticipant } from '../group-chat/group-chat-storage';
+import type { GroupChatState } from '../../shared/group-chat-types';
+import type { ParticipantState } from '../ipc/handlers/groupChat';
 
 // ==========================================================================
 // Constants
@@ -15,13 +22,6 @@ import type { ProcessManager } from '../process-manager';
  * Session IDs starting with this prefix belong to group chat sessions.
  */
 export const GROUP_CHAT_PREFIX = 'group-chat-';
-import type { WebServer } from '../web-server';
-import type { AgentDetector } from '../agent-detector';
-import type { SafeSendFn } from '../utils/safe-send';
-import type { StatsDB } from '../stats-db';
-import type { GroupChat, GroupChatParticipant } from '../group-chat/group-chat-storage';
-import type { GroupChatState } from '../../shared/group-chat-types';
-import type { ParticipantState } from '../ipc/handlers/groupChat';
 
 // Re-export types from their canonical locations
 export type { UsageStats, QueryCompleteData, ToolExecution } from '../process-manager/types';