feat: generate tool handlers (validate, pbjson decode, tonic call, pbjson encode) (#7)

examples/Cargo.toml

@@ -27,6 +27,26 @@ serde_json = "1"
 async-trait = "0.1"
 rmcp = { version = "3.5", default-features = false, features = ["server"] }
 futures = "0.3"
+# Validates tool call arguments against the generated input schema before
+# decoding them (see protoc-gen-rust-mcp/src/server.rs's module doc
+# comment): a runtime dependency of the generated handlers, not just this
+# crate's tests, so it's a normal (not dev-)dependency. No HTTP/file
+# `$ref` resolution is needed (every generated schema is self-contained),
+# hence `default-features = false`.
+jsonschema = { version = "0.58", default-features = false }
 
 [dev-dependencies]
 tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
+# "router" adds Server::builder()/add_service, to run a real in-process
+# tonic server in tests/handler.rs ("server" and "channel" are already
+# pulled in by [dependencies].tonic above).
+tonic = { version = "0.14", default-features = false, features = ["router"] }
+# tests/handler.rs drives the generated server through a real rmcp
+# client ("client") over an in-memory duplex transport
+# ("transport-io"), instead of calling the handler directly, so it
+# exercises the same wire path a real MCP client would. Needed here (in
+# addition to [dependencies]'s "server") so `cargo test -p examples`
+# compiles on its own, without relying on feature unification with
+# protoc-gen-rust-mcp's own dev-dependency on rmcp under
+# `cargo test --workspace`.
+rmcp = { version = "3.5", default-features = false, features = ["client", "transport-io"] }