feat(upgrade): add self-update command from Gitea Release

- Add secrets upgrade command: --check to verify, default to download and replace binary
- No database or master key required
- Support tar.gz and zip artifacts from Gitea Release

Made-with: Cursor

src/commands/mod.rs

@@ -6,3 +6,4 @@ pub mod rollback;
 pub mod run;
 pub mod search;
 pub mod update;
+pub mod upgrade;