docs: Remove duplicate installation steps from README

- Remove old numbered sections (#### 4, 5, 6) that duplicate Quick Setup Overview
- Keep only the streamlined Quick Setup Overview with 9 steps
- Add links to detailed guides at the end

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: shubham5080

README.md

@@ -189,8 +189,6 @@ Edit config: Set `github.org`, `discord.guild_id`, and `snapshots.repo_path`
 
 **7. Test Run (Dry-Run Mode)**
 
-#### 4. Configure and Run (Safe Dry‑Run)
-
 ```bash
 cp config/example.yaml /tmp/ghdcbot-config.yaml
 # Use the venv python explicitly to avoid alias/PATH issues