v3.1.0

• Experimental support for React 19. _debugSource was removed in React 19. The PR says that tools should lazily generate component stack strace, but I couldn't find a way to use the React devtools globals to generate one for a given Fiber node. I've aksed some React team members about insights on how to make this works, but for now I decided to patch the jsx dev runtime (when serving it) to reinject into Fiber node the source prop added by JSX transform.