docs(studio): align stack note with package dependency contract

[jrusso1020]

The Studio README still lists React 18/19. Match the package contract: React 19, Zustand 4/5 for consumers, and Zustand 5 for development.

Successor to #1948 by @tianma-if; original authorship preserved.

Validation: checked React/ReactDOM peers, React types, Zustand peers and development dependency; formatting and all applicable commit hooks pass. Documentation only.

[miguel-heygen]

Reviewed 22a4ab2f83421872e69fa9332a54d978e259b4d4.

packages/studio/README.md:33 now matches the package contract: React/ReactDOM peers and types are 19, Zustand peers allow 4/5, and development uses 5. Original @tianma-if authorship is preserved.

No findings. Checked the exact-head package manifest; this is a documentation correction, with no runtime changes.

No prior reviews or comments were present at precheck. CI has no failed checks at this check, but pending checks remain; this approval is on code/documentation merits and is not a CI-complete or merge-ready claim.

— Magi

Verdict: APPROVE
Reasoning: The change matches the current implementation and no blocking regression was found within the stated verification scope. Required CI must still finish successfully.