feat: implement logging throughout the linebot application

[yenslife]

This commit introduces a centralized logging system. A new module linebot/app/config/logger.py is created to configure and provide logger instances. The logging configuration includes:

• Log formatting with timestamp, logger name, level, and message.
• Console output with configurable log level.
• File output with rotating file handler (max 10MB, 5 backups).
• A global app_logger instance for general application logging.

The existing print statements in linebot/app/api/vision.py and linebot/app/routers/linebot.py are replaced with calls to the new logging system. This allows for better control and management of application logs.

Additionally, the .gitignore file is updated to ignore the logs/ directory, preventing log files from being committed to the repository.

[Copilot]

Pull Request Overview

This PR introduces a centralized logging system to replace print statements and standard logger calls with a uniform, configurable logging setup across the application.

• Introduces a new logger module that configures both console and rotating file handlers
• Replaces print statements with logger calls in message handling, API, and router modules

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
linebot/app/webhooks/handlers.py	Replaced print statements with logger.info calls
linebot/app/services/message_service.py	Updated logging initialization to use get_logger
linebot/app/services/handlers/text_handler.py	Switched to centralized logger for text message handling
linebot/app/services/handlers/image_handler.py	Replaced standard logging with get_logger usage
linebot/app/services/handlers/common.py	Updated logger initialization with get_logger
linebot/app/services/handlers/audio_handler.py	Replaced print statement with logger.info call
linebot/app/routers/linebot.py	Replaced print calls with logger calls for various events
linebot/app/config/logger.py	Introduced centralized logging configuration
linebot/app/api/vision.py	Replaced print with logger.error for error handling