refactor: centralize auth middleware and standardize logging

1. API Key Middleware (api.ts)
- Create apiKeyAuth Hono middleware with timing-safe comparison
- Apply to /deposit/balance and /deposit/deduct routes
- Remove duplicate requireApiKey() calls from handlers
- Reduce ~15 lines of duplicated code

2. Logger Standardization (6 files, 27 replacements)
- webhook.ts: 2 console.error → logger
- message-handler.ts: 7 console → logger
- deposit-matcher.ts: 4 console → logger
- n8n-service.ts: 3 console.error → logger
- circuit-breaker.ts: 8 console → logger
- retry.ts: 3 console → logger

Benefits:
- Single point of auth change
- Structured logging with context
- Better observability in production

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/utils/circuit-breaker.ts

@@ -1,5 +1,8 @@
 import { metrics } from './metrics';
 import { notifyAdmin, NotificationOptions } from '../services/notification';
+import { createLogger } from './logger';
+
+const logger = createLogger('circuit-breaker');
 
 /**
  * Circuit Breaker pattern implementation
@@ -99,7 +102,7 @@ export class CircuitBreaker {
     this.serviceName = options?.serviceName ?? 'unknown';
     this.notification = options?.notification;
 
-    console.log('[CircuitBreaker] Initialized', {
+    logger.info('Initialized', {
       serviceName: this.serviceName,
       failureThreshold: this.failureThreshold,
       resetTimeoutMs: this.resetTimeoutMs,
@@ -146,7 +149,7 @@ export class CircuitBreaker {
    * Manually reset the circuit to closed state
    */
   reset(): void {
-    console.log('[CircuitBreaker] Manual reset');
+    logger.info('Manual reset', { service: this.serviceName });
     this.state = CircuitState.CLOSED;
     this.failures = [];
     this.openedAt = null;
@@ -178,7 +181,10 @@ export class CircuitBreaker {
       const elapsed = now - this.openedAt;
 
       if (elapsed >= this.resetTimeoutMs) {
-        console.log('[CircuitBreaker] Reset timeout reached, transitioning to HALF_OPEN');
+        logger.info('Reset timeout reached, transitioning to HALF_OPEN', {
+          service: this.serviceName,
+          elapsedMs: elapsed
+        });
         this.state = CircuitState.HALF_OPEN;
 
         // 상태 메트릭 기록 (HALF_OPEN)
@@ -194,7 +200,9 @@ export class CircuitBreaker {
     this.successCount++;
 
     if (this.state === CircuitState.HALF_OPEN) {
-      console.log('[CircuitBreaker] Half-open test succeeded, closing circuit');
+      logger.info('Half-open test succeeded, closing circuit', {
+        service: this.serviceName
+      });
       this.state = CircuitState.CLOSED;
       this.failures = [];
       this.openedAt = null;
@@ -218,7 +226,10 @@ export class CircuitBreaker {
 
     // If in half-open state, one failure reopens the circuit
     if (this.state === CircuitState.HALF_OPEN) {
-      console.log('[CircuitBreaker] Half-open test failed, reopening circuit');
+      logger.warn('Half-open test failed, reopening circuit', {
+        service: this.serviceName,
+        error: error.message
+      });
       this.state = CircuitState.OPEN;
       this.openedAt = now;
 
@@ -246,9 +257,11 @@ export class CircuitBreaker {
     // Check if we should open the circuit
     if (this.state === CircuitState.CLOSED) {
       if (this.failures.length >= this.failureThreshold) {
-        console.log(
-          `[CircuitBreaker] Failure threshold (${this.failureThreshold}) exceeded, opening circuit`
-        );
+        logger.warn('Failure threshold exceeded, opening circuit', {
+          service: this.serviceName,
+          failureThreshold: this.failureThreshold,
+          currentFailures: this.failures.length
+        });
         this.state = CircuitState.OPEN;
         this.openedAt = now;
 
@@ -291,7 +304,9 @@ export class CircuitBreaker {
         'Circuit breaker is open - service unavailable',
         this.state
       );
-      console.log('[CircuitBreaker] Request blocked - circuit is OPEN');
+      logger.warn('Request blocked - circuit is OPEN', {
+        service: this.serviceName
+      });
       throw error;
     }
 
@@ -315,10 +330,11 @@ export class CircuitBreaker {
       this.onFailure(err);
 
       // Log failure
-      console.error(
-        `[CircuitBreaker] Operation failed (${this.failures.length}/${this.failureThreshold} failures):`,
-        err.message
-      );
+      logger.error('Operation failed', err, {
+        service: this.serviceName,
+        failures: this.failures.length,
+        threshold: this.failureThreshold
+      });
 
       // Re-throw the original error
       throw err;

src/utils/retry.ts

@@ -12,6 +12,9 @@
 
 import { metrics } from './metrics';
 import { notifyAdmin, NotificationOptions } from '../services/notification';
+import { createLogger } from './logger';
+
+const logger = createLogger('retry');
 
 /**
  * Configuration options for retry behavior
@@ -123,7 +126,11 @@ export async function retryWithBackoff<T>(
 
       // Log success if this was a retry
       if (attempt > 0) {
-        console.log(`[Retry] Success on attempt ${attempt + 1}/${maxRetries + 1}`);
+        logger.info('Success on retry', {
+          service: serviceName,
+          attempt: attempt + 1,
+          totalAttempts: maxRetries + 1
+        });
       }
 
       return result;
@@ -132,10 +139,10 @@ export async function retryWithBackoff<T>(
 
       // If this was the last attempt, throw RetryError
       if (attempt === maxRetries) {
-        console.error(
-          `[Retry] All ${maxRetries + 1} attempts failed. Last error:`,
-          lastError.message
-        );
+        logger.error('All attempts failed', lastError, {
+          service: serviceName,
+          totalAttempts: maxRetries + 1
+        });
 
         // Send admin notification if configured
         if (notification) {
@@ -176,10 +183,13 @@ export async function retryWithBackoff<T>(
         jitter
       );
 
-      console.log(
-        `[Retry] Attempt ${attempt + 1}/${maxRetries + 1} failed. Retrying in ${delay}ms...`,
-        lastError.message
-      );
+      logger.warn('Attempt failed, retrying', {
+        service: serviceName,
+        attempt: attempt + 1,
+        totalAttempts: maxRetries + 1,
+        delayMs: delay,
+        error: lastError.message
+      });
 
       // Wait before next retry
       await sleep(delay);