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/contract/Cargo.toml

@@ -1,5 +1,5 @@
 [package]
-name = "rhema-tools-contract"
+name = "rhema-claw-tools-contract"
 description = "The wire contract between the rhema claw daemon and its thin client tools: routes, shapes, the agent-token allowlist, and the conformance suite"
 version.workspace = true
 edition.workspace = true