fix(core): add missing core.proxy_file module used by CLI

[mkilijanek]

Summary

Fix a missing runtime module required by evilwaf.py.

Problem

evilwaf.py imports core.proxy_file.load_proxy_file, but core/proxy_file.py is not present in upstream. This can break startup when Python resolves imports.

Change

• add core/proxy_file.py with load_proxy_file(path) helper
• parser behavior:
  • trims whitespace
  • ignores empty lines
  • ignores comment lines beginning with #

Validation

• python3 -m py_compile evilwaf.py core/*.py chemistry/*.py

Risk

• low, additive module only
• no behavior changes outside proxy-file parsing path

[mkilijanek]

Suggested merge sequence anchor: start here for runtime stabilization.\n\nProposed order: #17 -> #18 -> #19 -> #20 -> #21 -> #22 -> #23 -> #24 -> #25 -> #26.