fix(ui): guard password/TLS prompt redraw while suspended

inp_get_line()/inp_get_password() issued an unconditional doupdate()
before their input loop. If such a prompt is raised while an external
editor is active (e.g. a reconnect password or TLS-cert prompt arriving
via session_process_events), that doupdate() writes over the editor and
clears isendwin(). Guard it with isendwin(), matching the _inp_write()
guard from the upstream "guard terminal writes while suspended" fix;
this closes the one suspended-write path upstream left open.

src/ui/inputwin.c

@@ -311,7 +311,10 @@ inp_get_line(void)
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();
-    doupdate();
+    // Don't write to the terminal while suspended (external editor active).
+    if (!isendwin()) {
+        doupdate();
+    }
     char* line = NULL;
     while (!line) {
         line = inp_readline();
@@ -338,7 +341,10 @@ inp_get_password(void)
     werase(inp_win);
     wmove(inp_win, 0, 0);
     _inp_win_update_virtual();
-    doupdate();
+    // Don't write to the terminal while suspended (external editor active).
+    if (!isendwin()) {
+        doupdate();
+    }
     char* password = NULL;
     get_password = TRUE;
     while (!password) {