Add .gitignore and remove sensitive/generated files

- Add comprehensive .gitignore file to exclude:
  * data-import/ directory with all CSV files
  * Database files (*.db)
  * Legacy data directories (old-csv/, old-database/)
  * Generated HTML files (rolodex.html, sync_result.html)
  * Temporary files (cookies.txt, test_upload.csv, etc.)
  * Python cache files (__pycache__/)
  * IDE and OS files (.vscode/, .DS_Store, etc.)
- Remove all previously tracked sensitive and generated files from git

.gitignore

@@ -0,0 +1,66 @@
+# Data and import files
+data-import/
+*.csv
+*.db
+cookies.txt
+phone_book.csv
+phone_book_address.csv
+test_upload.csv
+sync_result.html
+rolodex.html
+
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Virtual environments
+.env
+.venv
+env/
+venv/
+ENV/
+env.bak/
+venv.bak/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+
+# Logs
+*.log
+logs/
+
+# Temporary files
+*.tmp
+*.temp
+.cache/