Add log rotation support with multiple modes

[DiegoDAF]

Summary

This PR adds flexible log rotation support to pgcli, inspired by PostgreSQL's log_filename configuration and pgadmin4's implementation.

Features

New Configuration Options

1. log_rotation_mode - Controls how log files are rotated:

   • none (default) - Single log file pgcli.log (backward compatible)
   • day-of-week - Rotates by day name (Mon-Sun), overwrites weekly
   • day-of-month - Rotates by day number (01-31), overwrites monthly
   • date - Rotates by date (YYYYMMDD), never overwrites

2. log_destination - Specifies log directory:

   • default - Uses standard config location (~/.config/pgcli/log)
   • Custom path - Any valid directory

Characteristics

• Backward compatible: Works exactly as before without configuration
• System locale aware: Uses system's day names via strftime("%a")
• No automatic deletion: Old log files are never deleted automatically
• Flexible: Allows custom log directory location

Example Configuration

[main]
log_rotation_mode = day-of-week
log_destination = default

Generated Filenames

• none: pgcli.log
• day-of-week: pgcli-Mon.log, pgcli-Tue.log, etc.
• day-of-month: pgcli-01.log, pgcli-02.log, ..., pgcli-31.log
• date: pgcli-20250127.log, pgcli-20250128.log, etc.

Testing

Complete test coverage included:

• 5 pytest unit tests in tests/test_main.py
• 4 behave integration tests in tests/features/log_rotation.feature

Related Issues

Closes #1541 - This is the corrected and complete implementation with proper tests.