fix: declaring dependencies of a stata script

[tobiasraabe]

Summary

Closes #106

• Allow generated Stata task runners to accept arbitrary dependency keyword arguments.
• Add regression coverage for dependencies declared in the task signature and through @task(kwargs=...).
• Clarify README examples for dependency/product tracking versus passing values to Stata through options.

Root Cause

pytask-stata collected normal pytask dependency arguments for Stata tasks, but the generated run_stata_script function only accepted the plugin's internal keyword arguments. During execution, pytask passed user dependency names to that runner, causing TypeError: run_stata_script() got an unexpected keyword argument ... before Stata was invoked.