feat: implement dual-transport WAL architecture with permanent background leader and lightweight stubs

stub/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "mcp-memory-stub"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+clap = { version = "4.6.6", features = ["derive"] }
+reqwest = { version = "0.12", default-features = false, features = ["stream", "rustls-tls"] }
+tokio = { version = "1.53.1", features = ["full"] }
+tokio-util = { version = "0.7.19", features = ["io"] }
+futures-util = "0.3.34"