Upgrade lexical packages from 0.42.0 to 0.49.0

[dramoturg]

The current version of the editor relies on Meta's Lexical framework at version 0.42.0. There is a newer version available (0.49.0) that introduces important internal updates, bug fixes, and stability improvements.Upgrading the core and React wrapper dependencies would keep the project aligned with the upstream ecosystem.

Motivation & Reasons to Upgrade

1. React 19 Compatibility & Stability: lobe-editor is a modern framework targeting React 19+. Recent Lexical versions include refined internal hooks, updated event propagation, and type definitions explicitly tested against newer React environments, which prevents ecosystem friction.
2. Performance & Memory Optimization: Major revisions between 0.42.0 and 0.49.0 optimize the core garbage collection loop, node mutation tracking, and shadow DOM lifecycle management, improving responsiveness in heavy AI/Chat interfaces with streaming inputs.

Do you have plan to upgrade lexical version?

[github-actions]

👀 @dramoturg
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