chore: upgrade rmcp 1.8.0 -> 3.1.2

Compile-clean upgrade verified: zero source changes needed, full test
suite green, clippy clean. Coyote's rmcp API surface (14 items) dodges
all 2.0/3.0 breaking changes; the "Auth required" error string matched
by is_auth_required_error is intact in 3.1.2.

Cargo.lock

@@ -1962,6 +1962,16 @@ dependencies = [
  "darling_macro 0.23.0",
 ]
 
+[[package]]
+name = "darling"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "88490bf1b990d87eaaa7ac8aa887f629a08e7359765b4911faf63c3763347d23"
+dependencies = [
+ "darling_core 0.24.0",
+ "darling_macro 0.24.0",
+]
+
 [[package]]
 name = "darling_core"
 version = "0.20.11"
@@ -1989,6 +1999,19 @@ dependencies = [
  "syn 2.0.119",
 ]
 
+[[package]]
+name = "darling_core"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "084e274f91c482280130e1e34e0b8d6e66776a060d7b6de7b84289ca778868c4"
+dependencies = [
+ "ident_case",
+ "proc-macro2",
+ "quote",
+ "strsim",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "darling_macro"
 version = "0.20.11"
@@ -2011,6 +2034,17 @@ dependencies = [
  "syn 2.0.119",
 ]
 
+[[package]]
+name = "darling_macro"
+version = "0.24.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68f5792fa0d41cd2325ce0ffa64f0a340eaebd4971a3a0c5e1ffd2cc488a355e"
+dependencies = [
+ "darling_core 0.24.0",
+ "quote",
+ "syn 3.0.3",
+]
+
 [[package]]
 name = "defmt"
 version = "1.1.1"
@@ -5303,12 +5337,12 @@ dependencies = [
 
 [[package]]
 name = "rmcp"
-version = "1.8.0"
+version = "3.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d1f571c72940a19d9532fe52dbea8bc9912bf1d766c2970bb824056b86f3f59"
+checksum = "c8dddc5b1924b9a59fba420166160ca2c4663a4e01803e52eda33070f56d63c8"
 dependencies = [
- "async-trait",
- "base64 0.22.1",
+ "base64 0.23.1",
+ "bytes",
  "chrono",
  "futures",
  "http 1.5.0",
@@ -5326,19 +5360,20 @@ dependencies = [
  "tokio-stream",
  "tokio-util",
  "tracing",
+ "uuid",
 ]
 
 [[package]]
 name = "rmcp-macros"
-version = "1.8.0"
+version = "3.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1aad0035b69380782d78ea95b508327e6deaa2235909053e596eea8f27b5e1d5"
+checksum = "6898e24cd16342b59bfa8a53c2c04b9cf62fc8a2cfea57b9c038b09984bfc521"
 dependencies = [
- "darling 0.23.0",
+ "darling 0.24.0",
  "proc-macro2",
  "quote",
  "serde_json",
- "syn 2.0.119",
+ "syn 3.0.3",
 ]
 
 [[package]]

Cargo.toml

@@ -84,7 +84,7 @@ duct = "1.0.0"
 argc = "1.23.0"
 strum_macros = "0.27.2"
 indoc = "2.0.6"
-rmcp = { version = "1.5.0", features = [
+rmcp = { version = "3.1.2", features = [
   "client",
   "transport-child-process",
   "transport-streamable-http-client-reqwest",