feat(cli): add Gitea API client for deploy keys

Create, delete, and list deploy keys via Gitea REST API.
Foundation for device authentication.

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

crates/relicario-cli/Cargo.toml

@@ -17,7 +17,6 @@ arboard = "3"
 chrono = { version = "0.4", default-features = false, features = ["clock"] }
 dirs = "5"
 hex = "0.4"
-ed25519-dalek = { version = "2", features = ["rand_core"] }
 rand = "0.8"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
@@ -28,6 +27,7 @@ tar = { version = "0.4", default-features = false }
 clap_complete = "4"
 image = { version = "0.25", default-features = false, features = ["jpeg", "png"] }
 rqrr = "0.7"
+reqwest = { version = "0.12", features = ["blocking", "json"] }
 
 [dev-dependencies]
 assert_cmd = "2"