[ZEPPELIN-6738] Upgrade React to 19 and fix shared host integration

[voidmatcha]

What is this PR for?

Upgrade the React remote to React 19 and fix shared integration behavior between the Angular host and React surfaces.

These changes were identified during the notebook Assistant frontend work and are separated from that feature so they can be merged without its server changes.

• Upgrade React, ReactDOM and their type definitions, with Ant Design compatibility updates.
• Preserve host callback return values and stable wrapper identity so subscriptions can clean up correctly and avoid unnecessary restarts.
• Extract the existing 401 redirect and 405 logout policy into TicketService.handleAuthFailure, preserving logout guards. This prepares a shared entry point for later remote integrations; connecting Assistant requests is outside this PR.
• Commit React theme updates before the next paint and temporarily suppress document-wide CSS transitions during theme switching.

The callback, authentication and theme fixes do not inherently require React 19.

What type of PR is it?

Improvement

Todos

• Complete automated verification on the PR branch.
• Check existing Ant Design surfaces and rapid theme switching in a browser.

What is the Jira issue?

ZEPPELIN-6738

How should this be tested?

• Run the React unit tests, typecheck and lint.
• Run the Angular shell tests and SDK contract typecheck.
• Build the React remote and Angular application.

Production builds passed on the prerequisite branch. Chrome checks passed for repository form editing and cancellation, Select interaction, configuration table rendering and 18 rapid theme toggles, with no page errors.

Repository and configuration responses used browser-local fixtures because the QA repository list was empty. No server settings were saved.

Screenshots (if appropriate)

N/A

Questions:

• Does the license files need to update? No
• Is there breaking changes for older versions? No
• Does this needs documentation? No