[Docs] Fix broken markdown and trailing AI-assistant text in docs/DEVELOPMENT.md

[grantfox-oss]

Telegram (ask questions / claim the issue here first): https://t.me/+DOylgFv1jyJlNzM0

Why this matters

docs/DEVELOPMENT.md is wrapped in a stray opening fence at line 1 with a mismatched 4-backtick close on the clone block (lines 30-32), which breaks code-block rendering, and it ends with leftover generation chatter at lines 244-249 (If you want next-level polish, I can turn this into: - a Makefile / task runner ... - or a Dockerized full-stack dev environment).

Acceptance criteria

• Remove the outer wrapper fence and fix the mismatched clone code fence so all code blocks render
• Delete the trailing If you want next-level polish... assistant chatter
• Render the file to confirm clean formatting

Files to touch

• docs/DEVELOPMENT.md

Out of scope

• Changing the actual setup steps