Expose Post History in Topics API

[charliez07]

Summary

This PR implements the ability to view previous versions of edited posts by exposing post history metadata through the Topics API.

Changes Made

Core Implementation (src/topics/posts.js)

• Enhanced Topics.addPostData: Now includes post history metadata for all posts
  • hasHistory: Boolean indicating if post has revision history
  • revisionCount: Number of revisions available
  • canViewHistory: Boolean based on user privileges and settings
• Added Topics.getPostRevisions: New method to retrieve detailed revision information using existing Posts.diffs infrastructure
• Privilege Integration: Respects meta.config.enablePostHistory setting and user permissions

Test Coverage (test/topics.js)

• Added comprehensive test suite for post history functionality
• Tests history metadata inclusion in post objects
• Tests detailed revision retrieval
• Tests privilege-based access control

Technical Details

• Leverages existing Posts.diffs system for revision storage
• Maintains backward compatibility - no breaking changes
• Follows NodeBB patterns for privilege checking and data aggregation
• All functionality is controlled by the enablePostHistory config setting

User Story Fulfilled

✅ "As a user, I want to see previous versions of an edited post, so that I know what changed"

Users can now access post history through the Topics API when the feature is enabled and they have appropriate privileges.

[aarzate2]

I actually dont think this actually added this feature? I ran it in the code space, and I dont see anything new in regards to seeing post history, that wasnt already a feature.