Add outline-cli: minimal CLI for search and document retrieval

Adds a command-line client in cli/ as its own Cargo workspace, depending
on the outline library via a path dependency. Covers exactly the requested
scope: login (stores the API key in the system keyring via the Secret
Service D-Bus protocol, verified against auth.info() before storing),
search (full-text), and get (fetch a document, render its markdown to a
self-contained HTML page, open it in the default browser).

Verified end-to-end against a real Outline instance and the local
gnome-keyring: login stores and search/get retrieve the token purely from
the keyring and saved config, with no environment variables set.

cli/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "outline-cli"
+version = "0.1.0"
+edition = "2024"
+rust-version = "1.85"
+publish = false
+
+[workspace]
+
+[[bin]]
+name = "outline"
+path = "src/main.rs"
+
+[dependencies]
+outline-sdk = { path = "..", default-features = false, features = ["rustls-tls"] }
+anyhow = "1"
+clap = { version = "4.6", features = ["derive", "env"] }
+directories = "6"
+open = "5.4"
+pulldown-cmark = { version = "0.13", default-features = false, features = ["html"] }
+rpassword = "7.5"
+secret-service = { version = "5.1", features = ["rt-tokio-crypto-rust"] }
+serde = { version = "1", features = ["derive"] }
+toml = "1"
+tokio = { version = "1", features = ["rt", "macros"] }
+url = "2"
+
+[dev-dependencies]
+serde_json = "1"