fix: surface window-unavailable error instead of generic send error in SSH prompt

When the main window is destroyed during the IPC send/focus path,
the catch handler now checks if the thrown error is a window-unavailable
message and returns DesktopSshPromptWindowUnavailableError instead of
wrapping it in DesktopSshPromptSendError. This ensures the user sees
the correct window-unavailable explanation rather than a generic
send failure message.

Author: cursoragent

apps/desktop/src/ssh/DesktopSshPasswordPrompts.ts

@@ -340,12 +340,21 @@ export const make = Effect.fn("desktop.sshPasswordPrompts.make")(function* (
         }
         window.value.focus();
       },
-      catch: (cause) =>
-        new DesktopSshPromptSendError({
+      catch: (cause) => {
+        if (
+          cause instanceof Error &&
+          cause.message === windowUnavailableMessage(input.destination)
+        ) {
+          return new DesktopSshPromptWindowUnavailableError({
+            destination: input.destination,
+          });
+        }
+        return new DesktopSshPromptSendError({
           requestId,
           destination: input.destination,
           cause,
-        }),
+        });
+      },
     }).pipe(Effect.andThen(waitForPassword), Effect.ensuring(cleanup));
   });