Implement connection flow, test connection, and secret prompts

- Change ConnectSession/ConnectQuick to return SessionInfo (not string)
- Change UpdateProfile to return (Profile, error) for frontend use
- Make session connection asynchronous to avoid Wails event loop deadlock
- Implement event-based secret prompt (backend ↔ frontend via requestID)
- Add TestConnection API for TCP reachability checks with latency
- Add 'Save & Connect' button in profile editor
- Wire _testConnection to real backend TCP check
- Add btn-accent CSS for the green action button

frontend/wailsjs/go/api/Service.d.ts

@@ -7,9 +7,9 @@ export function ClearSessionHistory(arg1:string):Promise<void>;
 
 export function CloseAllSessions():Promise<void>;
 
-export function ConnectQuick(arg1:models.Profile):Promise<string>;
+export function ConnectQuick(arg1:models.Profile):Promise<models.SessionInfo>;
 
-export function ConnectSession(arg1:string):Promise<string>;
+export function ConnectSession(arg1:string):Promise<models.SessionInfo>;
 
 export function CreateProfile(arg1:models.Profile):Promise<models.Profile>;
 
@@ -65,6 +65,8 @@ export function PinSession(arg1:string,arg2:boolean):Promise<void>;
 
 export function ReconnectSession(arg1:string):Promise<void>;
 
+export function RegisterSecretResponseListener():Promise<void>;
+
 export function RenameSession(arg1:string,arg2:string):Promise<void>;
 
 export function ResizeSession(arg1:string,arg2:number,arg3:number):Promise<void>;
@@ -87,9 +89,11 @@ export function SetFavourite(arg1:string,arg2:boolean):Promise<void>;
 
 export function SetProfileSecret(arg1:string,arg2:string,arg3:string):Promise<void>;
 
+export function TestConnection(arg1:string,arg2:number):Promise<Record<string, any>>;
+
 export function UnlockSecretStore(arg1:string):Promise<void>;
 
-export function UpdateProfile(arg1:models.Profile):Promise<void>;
+export function UpdateProfile(arg1:models.Profile):Promise<models.Profile>;
 
 export function WriteSession(arg1:string,arg2:string):Promise<void>;
 

frontend/wailsjs/go/api/Service.js

@@ -126,6 +126,10 @@ export function ReconnectSession(arg1) {
   return window['go']['api']['Service']['ReconnectSession'](arg1);
 }
 
+export function RegisterSecretResponseListener() {
+  return window['go']['api']['Service']['RegisterSecretResponseListener']();
+}
+
 export function RenameSession(arg1, arg2) {
   return window['go']['api']['Service']['RenameSession'](arg1, arg2);
 }
@@ -170,6 +174,10 @@ export function SetProfileSecret(arg1, arg2, arg3) {
   return window['go']['api']['Service']['SetProfileSecret'](arg1, arg2, arg3);
 }
 
+export function TestConnection(arg1, arg2) {
+  return window['go']['api']['Service']['TestConnection'](arg1, arg2);
+}
+
 export function UnlockSecretStore(arg1) {
   return window['go']['api']['Service']['UnlockSecretStore'](arg1);
 }