feat(server): add relicario-server for pre-receive hook

- verify-commit command checks signature against devices.json
- generate-hook outputs installable pre-receive script
- Foundation for server-side enforcement

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

crates/relicario-server/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "relicario-server"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+relicario-core = { path = "../relicario-core" }
+anyhow = "1"
+clap = { version = "4", features = ["derive"] }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"