refactor(tools): rename rhema-tools-contract to rhema-claw-tools-contract

The crate binds the claw to its client tools, not tools at large,
so it carries the claw's name: package, lib and dep names, the
mock's binary, and the conformance suite's use paths. Specs and
README follow. The tools/contract directory keeps its name, and
no reference to the old name remains.

tools/notify/Cargo.toml

@@ -14,7 +14,7 @@ path = "src/main.rs"
 
 [dependencies]
 rhema-tools-common = { path = "../common" }
-rhema-tools-contract = { path = "../contract" }
+rhema-claw-tools-contract = { path = "../contract" }
 clap.workspace = true
 serde.workspace = true
 serde_json.workspace = true