feat(logging): replace 207 console.log/error/warn with pino structured logger (#58)

- Add pino + pino-pretty dependencies
- Create src/utils/logger.js with env-based LOG_LEVEL
- Replace all 207 console.log/error/warn calls across 46 source files
- Remove [DEBUG], [ERROR] string prefixes (levels convey this)
- Add pino redact for sensitive fields (mnemonic, privateKey, token, etc.)
- Structured logging with context objects instead of string interpolation
- NODE_ENV=production disables pino-pretty transport

49 files changed, 5601 insertions, 6056 deletions

src/utils/errorHandler.js

@@ -1,6 +1,8 @@
+import logger from './logger.js';
+
 export default class ErrorHandler {
   static async handleError(bot, chatId, error, context) {
-    console.error(`Error in ${context}:`, error);
+    logger.error({ err: error, context }, 'Error in handler');
     
     const errorMessage = process.env.NODE_ENV === 'development' 
       ? `Error: ${error.message}`
@@ -9,16 +11,16 @@ export default class ErrorHandler {
     try {
       await bot.sendMessage(chatId, errorMessage);
     } catch (sendError) {
-      console.error('Error sending error message:', sendError);
+      logger.error({ err: sendError }, 'Error sending error message');
     }
   }
 
   static handlePollingError(error) {
     if (error.code === 'ETELEGRAM') {
-      console.error('Telegram API Error:', error.message);
+      logger.error({ err: error }, 'Telegram API Error');
       process.exit(1);
     } else {
-      console.error('Polling error:', error);
+      logger.error({ err: error }, 'Polling error');
     }
   }
 }