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/src/main.rs

@@ -4,6 +4,7 @@
 
 mod helpers;
 mod session;
+mod gitea;
 
 use std::path::PathBuf;