Follow-up to PR #13: remove auto declaration injection from test setup and rely on include-style test harness

[NickK21]

Summary

PR #13 fixed duplicate-linking for include-style C++ tests (runner.cpp + program.cpp), but C++ test setup still auto-injects regex-generated declarations into test_program.h. That injection can generate incorrect signatures (example: unsigned int reduced to int) and cause compile errors unrelated to student correctness.

Current behavior

In executor.js:

• extractFunctionDeclarations() parses student code with regex.
• handleTestSetup() prepends generated declarations to testCode.
• test_program.h becomes declarations + testCode.

This can introduce conflicts even when testCode correctly uses include-style harness logic.

Desired behavior

• Remove declaration injection for C++ tests.
• Let testCode fully own adaptation logic (#include "program.cpp", #define main ..., cin/cout capture, etc.).
• Keep PR CPP compilation excludes redundant code submission file, fixes codewit-us/codewit.us#152 #13 link behavior (compile runner only).

This issue is a follow-up to PR #13.