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/DATABASE_POPULATION_SUCCESS.md

@@ -45,7 +45,7 @@ python3 scripts/import_flipper_sqlite.py
 FLIPPER ZERO → SQLite IMPORT
 ================================================================================
 
-Database: /home/dell/coding/giglez/giglez.db
+Database: /path/to/giglez/giglez.db
 ✅ Connected to SQLite database
 
 Creating schema...
@@ -76,7 +76,7 @@ FREQUENCY DISTRIBUTION
   433.92 MHz:  84 devices
   868.35 MHz:   1 devices
 
-✅ Database ready at: /home/dell/coding/giglez/giglez.db
+✅ Database ready at: /path/to/giglez/giglez.db
 ```
 
 **Result**: 100% success rate - all 85 Flipper Zero signatures imported!