fix: post-plugins-merge cleanroom fixes and workspace deps

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

rust/Cargo.toml

@@ -8,6 +8,9 @@ edition = "2021"
 license = "MIT"
 publish = false
 
+[workspace.dependencies]
+serde_json = "1"
+
 [workspace.lints.rust]
 unsafe_code = "forbid"