jwt implementation and login, not working yet

common/proto/auth.proto

@@ -6,6 +6,7 @@ import "common.proto";
 
 service AuthService {
     rpc Register(RegisterRequest) returns (AuthResponse);
+    rpc Login(LoginRequest) returns (LoginResponse);
 }
 
 message RegisterRequest {
@@ -21,3 +22,16 @@ message AuthResponse {
     string email = 3;        // Registered email (if provided)
     string role = 4;         // Default role: 'accountant'
 }
+
+message LoginRequest {
+    string identifier = 1;   // Can be username or email
+    string password = 2;
+}
+
+message LoginResponse {
+    string access_token = 1;   // JWT token
+    string token_type = 2;     // Usually "Bearer"
+    int32 expires_in = 3;      // Expiration in seconds (86400 for 24 hours)
+    string user_id = 4;        // User's UUID in string format
+    string role = 5;           // User's role
+}