refactor: deduplicate logger into shared module (#39)

three files created identical pino logger instances with the same config.
extract into src/logger.ts and import from each consumer.

net -9 lines, no behavior change.

Co-authored-by: ejae <ejae_dev@ejaes-Mac-mini.home>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

src/logger.ts

@@ -0,0 +1,6 @@
+import pino from 'pino';
+
+export const logger = pino({
+  level: process.env.LOG_LEVEL || 'info',
+  transport: { target: 'pino-pretty', options: { colorize: true } },
+});