feat: implement Phase 2 test structure and modules

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

src/tests/server/api_tests.rs

@@ -0,0 +1 @@
+// Server API tests

src/tests/server/auth_tests.rs

@@ -0,0 +1 @@
+// Server authentication tests

src/tests/server/mod.rs

@@ -0,0 +1,6 @@
+// Server tests module
+
+#[cfg(test)]
+pub mod api_tests;
+#[cfg(test)]
+pub mod auth_tests;