refactor(auth): replace manual input handling with AsyncPrompt for callback URLs

internal/auth/gemini/gemini_auth.go

@@ -329,18 +329,7 @@ waitForCallback:
 				return nil, err
 			default:
 			}
-			inputCh := make(chan string, 1)
+			manualInputCh, manualInputErrCh = misc.AsyncPrompt(opts.Prompt, "Paste the Gemini callback URL (or press Enter to keep waiting): ")
-			inputErrCh := make(chan error, 1)
-			go func() {
-				input, err := opts.Prompt("Paste the Gemini callback URL (or press Enter to keep waiting): ")
-				if err != nil {
-					inputErrCh <- err
-					return
-				}
-				inputCh <- input
-			}()
-			manualInputCh = inputCh
-			manualInputErrCh = inputErrCh
 			continue
 		case input := <-manualInputCh:
 			manualInputCh = nil

internal/misc/oauth.go

@@ -30,6 +30,23 @@ type OAuthCallback struct {
 	ErrorDescription string
 }
 
+// AsyncPrompt runs a prompt function in a goroutine and returns channels for
+// the result. The returned channels are buffered (size 1) so the goroutine can
+// complete even if the caller abandons the channels.
+func AsyncPrompt(promptFn func(string) (string, error), message string) (<-chan string, <-chan error) {
+	inputCh := make(chan string, 1)
+	errCh := make(chan error, 1)
+	go func() {
+		input, err := promptFn(message)
+		if err != nil {
+			errCh <- err
+			return
+		}
+		inputCh <- input
+	}()
+	return inputCh, errCh
+}
+
 // ParseOAuthCallback extracts OAuth parameters from a callback URL.
 // It returns nil when the input is empty.
 func ParseOAuthCallback(input string) (*OAuthCallback, error) {

sdk/auth/antigravity.go

@@ -118,18 +118,7 @@ waitForCallback:
 				break waitForCallback
 			default:
 			}
-			inputCh := make(chan string, 1)
+			manualInputCh, manualInputErrCh = misc.AsyncPrompt(opts.Prompt, "Paste the antigravity callback URL (or press Enter to keep waiting): ")
-			inputErrCh := make(chan error, 1)
-			go func() {
-				input, errPrompt := opts.Prompt("Paste the antigravity callback URL (or press Enter to keep waiting): ")
-				if errPrompt != nil {
-					inputErrCh <- errPrompt
-					return
-				}
-				inputCh <- input
-			}()
-			manualInputCh = inputCh
-			manualInputErrCh = inputErrCh
 			continue
 		case input := <-manualInputCh:
 			manualInputCh = nil

sdk/auth/claude.go

@@ -152,18 +152,7 @@ waitForCallback:
 				return nil, err
 			default:
 			}
-			inputCh := make(chan string, 1)
+			manualInputCh, manualInputErrCh = misc.AsyncPrompt(opts.Prompt, "Paste the Claude callback URL (or press Enter to keep waiting): ")
-			inputErrCh := make(chan error, 1)
-			go func() {
-				input, errPrompt := opts.Prompt("Paste the Claude callback URL (or press Enter to keep waiting): ")
-				if errPrompt != nil {
-					inputErrCh <- errPrompt
-					return
-				}
-				inputCh <- input
-			}()
-			manualInputCh = inputCh
-			manualInputErrCh = inputErrCh
 			continue
 		case input := <-manualInputCh:
 			manualInputCh = nil

sdk/auth/codex.go

@@ -155,18 +155,7 @@ waitForCallback:
 				return nil, err
 			default:
 			}
-			inputCh := make(chan string, 1)
+			manualInputCh, manualInputErrCh = misc.AsyncPrompt(opts.Prompt, "Paste the Codex callback URL (or press Enter to keep waiting): ")
-			inputErrCh := make(chan error, 1)
-			go func() {
-				input, errPrompt := opts.Prompt("Paste the Codex callback URL (or press Enter to keep waiting): ")
-				if errPrompt != nil {
-					inputErrCh <- errPrompt
-					return
-				}
-				inputCh <- input
-			}()
-			manualInputCh = inputCh
-			manualInputErrCh = inputErrCh
 			continue
 		case input := <-manualInputCh:
 			manualInputCh = nil

sdk/auth/iflow.go

@@ -131,18 +131,7 @@ waitForCallback:
 				return nil, fmt.Errorf("iflow auth: callback wait failed: %w", err)
 			default:
 			}
-			inputCh := make(chan string, 1)
+			manualInputCh, manualInputErrCh = misc.AsyncPrompt(opts.Prompt, "Paste the iFlow callback URL (or press Enter to keep waiting): ")
-			inputErrCh := make(chan error, 1)
-			go func() {
-				input, errPrompt := opts.Prompt("Paste the iFlow callback URL (or press Enter to keep waiting): ")
-				if errPrompt != nil {
-					inputErrCh <- errPrompt
-					return
-				}
-				inputCh <- input
-			}()
-			manualInputCh = inputCh
-			manualInputErrCh = inputErrCh
 			continue
 		case input := <-manualInputCh:
 			manualInputCh = nil