Workspace skeleton for plugins: sausage-vfs, sausage-interface, sausage-plugin, sausage-plugin-macros

The agent leaves the workspace until it is rewritten on the new SDK.

interface/src/compat.rs

@@ -0,0 +1,2 @@
+//! The compatibility check between a consumer's import and a provider's
+//! interface (PROPOSAL.md, section 11.2).

interface/src/lib.rs

@@ -0,0 +1,4 @@
+//! Sausage plugin interfaces: OpenRPC documents, the compatibility check
+//! (`compat`), and the generator of client code for `import!`.
+
+pub mod compat;