[FR] Add Built-in Spell Checker with Real-Time Suggestions to AppFlowy Editor

### Description

This feature introduces a complete Spell Checker system in the AppFlowy Editor, providing real-time spell checking, underline styling for misspelled words, and suggestion popups

### Impact

Spell checking significantly reduces typos and improves clarity, leading to more polished and professional documents. This benefits anyone who uses AppFlowy for writing—students, professionals, researchers, and teams.

### Additional Context

_No response_