feat(tools): notify — the first client tool

Desktop notifications are the wave-1 built-in the resident has no
native way to send: the daemon's pushes land in the poll queue, and
this is the program that turns one into an OS notification —
`notify push --title --body [--device]` on the shared plumbing, the
claw's `POST /v1/notifications` on the far end.

The binary is the template for every later client: connection from
the environment the daemon provisions, one contract-headered call,
JSON or error shape, exit code. The e2e test drives the real binary
against a mock claw — a wrong token is a 401 with the code to match,
a consent route is a 403, a good push prints the row — so a packaging
regression cannot pass silently. `skills/` ships the markdown that
teaches the agent the tool exists and what its answers mean.

tools/Cargo.toml

@@ -0,0 +1,24 @@
+[workspace]
+resolver = "2"
+members = ["contract", "common", "notify"]
+
+[workspace.package]
+version = "0.1.0"
+edition = "2024"
+rust-version = "1.85"
+license = "MIT"
+repository = "https://github.com/vhaudiquet/rhema"
+authors = ["Valentin Haudiquet"]
+
+[workspace.dependencies]
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+thiserror = "2"
+tokio = { version = "1", features = ["macros", "rt"] }
+# The thin clients' HTTP: loopback, no TLS (the contract is bearer-over-HTTP
+# to a loopback or otherwise trusted daemon; a remote TLS endpoint is a
+# stated non-goal v1).
+ureq = { version = "2", default-features = false, features = ["json"] }
+# Command-line surfaces and their test harness
+clap = { version = "4", features = ["derive"] }
+axum = { version = "0.8", features = ["json"] }