security: sanitize personal paths and usernames from documentation

Replaced all instances of:
- /home/dell/coding/giglez → /path/to/giglez
- /home/dell → ~
- leetcrypt → your-username
- PreistlyPython → your-username
- dell@ → user@

Affected files:
- 17 documentation files in docs/
- 2 shell scripts (download_rf_test_datasets.sh, start_web.sh)

No functional changes, only path/username sanitization for privacy.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

docs/PHASE2_PROGRESS.md

@@ -260,7 +260,7 @@ Development Mode (Termux)      Production Mode (Server)
 
 ### 1. Install Dependencies
 ```bash
-cd /home/dell/coding/giglez
+cd /path/to/giglez
 pip install -r requirements.txt
 pip install python-multipart  # For file uploads
 ```