Add Cargo workspace + common crate with Mode and Method types

Cargo.toml

@@ -0,0 +1,28 @@
+[workspace]
+resolver = "2"
+members = ["common", "daemon", "cli", "gui"]
+# GUI excluded from default builds because it requires libgtk-4-dev + libadwaita-1-dev
+# at link time. Build it explicitly with `cargo build -p ubuntu-fido-gui`.
+default-members = ["common", "daemon", "cli"]
+
+[workspace.package]
+version = "0.1.0"
+edition = "2021"
+license = "Apache-2.0"
+authors = ["Dangerous Things <ops@dangerousthings.com>"]
+repository = "https://github.com/dangerousthings/ubuntu-fido"
+rust-version = "1.78"
+
+[workspace.dependencies]
+zbus = "4"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+toml = "0.8"
+anyhow = "1"
+thiserror = "1"
+tracing = "0.1"
+tracing-subscriber = { version = "0.3", features = ["env-filter"] }
+tokio = { version = "1", features = ["full"] }
+clap = { version = "4", features = ["derive"] }
+ctap-hid-fido2 = "3"
+nix = { version = "0.28", features = ["user", "process", "fs"] }