fix: make passphrase optional for Unlock (#119)

* fix: make passphrase optional for Unlock

* CHANGELOG

Author: Vvaradinov

CHANGELOG.md

@@ -39,6 +39,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ### Improvements
 
+* [#119](https://github.com/babylonlabs-io/covenant-emulator/pull/119) Make passphrase for Unlock optional.
 * [#116](https://github.com/babylonlabs-io/covenant-emulator/pull/116) Add health check to prometheus server.
 * [#117](https://github.com/babylonlabs-io/covenant-emulator/pull/117) Add health check on startup, increase gas adjustment and update docs.
 

covenant-signer/signerservice/types/unlock.go

@@ -1,7 +1,10 @@
 package types
 
+// UnlockRequest represents a request to unlock the key.
+// Note: When using the file keyring backend, the passphrase will be prompted
+// interactively in the terminal, so it doesn't need to be included in this request.
 type UnlockRequest struct {
-	Passphrase string `json:"passphrase"`
+	Passphrase string `json:"passphrase,omitempty"`
 }
 
 type UnlockResponse struct{}