different log level per package

**Is your feature request related to a problem? Please describe.**
Currently I parse the log level from `GO_LOG` so users can specify it from environment variable eg as `GO_LOG=DEBUG go run`
But I want to specify log level per package as we can do with Rust log:

**Describe the solution you'd like**

Option to set log level for specific modules/packages
```console
RUST_LOG=package_name=DEBUG,other_package=INFO` cargo run # Log level per package
RUST_LOG=DEBUG` cargo run # Global log level
```

**Describe alternatives you've considered**
A clear and concise description of any alternative solutions or features you've considered.

**Additional context**
I don't know if currently it's even possible to change other loggers

Start by reading the existing GO_LOG parsing and logging entry points to understand how a global level is applied. Define how package-specific levels should coexist with the global setting, using the RUST_LOG examples as the behavioral reference. Done should include documented package-level and global configuration behavior, with tests covering both.

Written by the indexing model from the issue text.