fix(test): add env_lock to plugin lifecycle test — closes ROADMAP #24

build_runtime_runs_plugin_lifecycle_init_and_shutdown was the only test
that set/removed ANTHROPIC_API_KEY without holding the env_lock mutex.
Under parallel workspace execution, other tests racing on the same env
var could wipe the key mid-construction, causing a flaky credential error.

Root cause: process-wide env vars are shared mutable state. All other
tests that touch ANTHROPIC_API_KEY already use env_lock(). This test
was the only holdout.

Fix: add let _guard = env_lock(); at the top of the test.

rust/crates/rusty-claude-cli/src/main.rs

@@ -10816,6 +10816,9 @@ UU conflicted.rs",
 
     #[test]
     fn build_runtime_runs_plugin_lifecycle_init_and_shutdown() {
+        // Serialize access to process-wide env vars so parallel tests that
+        // set/remove ANTHROPIC_API_KEY do not race with this test.
+        let _guard = env_lock();
         let config_home = temp_dir();
         // Inject a dummy API key so runtime construction succeeds without real credentials.
         // This test only exercises plugin lifecycle (init/shutdown), never calls the API.