Removed numerous local image and document files from content posts and updated markdown files to reference external image and document URLs instead. This reduces repository size and centralizes media hosting, improving maintainability.

Added the content and images for Newsletter #51, covering topics on advanced data structures, algorithm performance, AI-assisted coding, HTTP complexity, and building a neural embedding search engine. Updated CLAUDE.md to allow 6-7 tags per post and clarified tag selection guidelines. Adjusted .claude/settings.local.json MCP server settings.