feat: implement Phase 2 test structure and modules

Co-authored-by: aider (openai/andrew/openrouter/qwen/qwen3-coder) <aider@aider.chat>

src/tests/common/mod.rs

@@ -1 +1,6 @@
 // Common test utilities and shared test code will go here
+
+#[cfg(test)]
+pub mod is_binary_tests;
+#[cfg(test)]
+pub mod status_tests;