feat: implement Phase 2 test structure and modules

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

src/tests/meta_plugin/digest_tests.rs

@@ -0,0 +1 @@
+// Meta plugin digest tests

src/tests/meta_plugin/mod.rs

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+// Meta plugin tests module
+
+#[cfg(test)]
+pub mod system_tests;
+#[cfg(test)]
+pub mod digest_tests;
+#[cfg(test)]
+pub mod program_tests;

src/tests/meta_plugin/program_tests.rs

@@ -0,0 +1 @@
+// Meta plugin program tests

src/tests/meta_plugin/system_tests.rs

@@ -0,0 +1 @@
+// Meta plugin system tests