Expand .dockerignore with standard entries

.dockerignore

@@ -1,11 +1,49 @@
-.git/
+# Python
+__pycache__/
+*.pyc
+*.pyo
+*.pyd
 .venv/
 venv/
+*.egg-info/
+.pytest_cache/
+
+# Tests
+backend/tests/
+
+# Environment & secrets
 .env
+*.env.local
+
+# Databases
+*.db
+*.sqlite3
+
+# Logs
+logs/
+*.log
+
+# IDE
+.idea/
+.vscode/
+
+# Git
+.git/
+.gitignore
+
+# Frontend
 frontend/node_modules/
 frontend/dist/
-backend/__pycache__/
-backend/**/__pycache__/
-backend/*.pyc
-backend/test.db
-backend/tests/
+
+# Docker
+docker-compose.yml
+.dockerignore
+
+# Docs
+*.md
+
+# Dev & build scripts
+run_dev.py
+build_push.sh
+start.sh
+test_api.sh