Remove env_logger dependency and implement custom logger

[sile]

This PR replaces the env_logger dependency with a lightweight custom logger implementation that:

• Provides colored output (ERROR, WARN, INFO, DEBUG, TRACE) with proper alignment
• Outputs timestamps in ISO 8601 UTC format
• Supports verbose mode for debug-level logging
• Removes unnecessary transitive dependencies (anstream, anstyle, jiff, etc.)