chore: add .dockerignore file to exclude build artifacts and environment files

.dockerignore

@@ -0,0 +1,31 @@
+.git
+.github
+.vscode
+.agent
+
+.env
+.env.*
+!.env.example
+!.env.secrets.example
+
+venv
+.venv
+.uv-cache
+.uv-python
+.pytest_cache
+.ruff_cache
+.mypy_cache
+__pycache__
+
+.npm-cache
+frontend/node_modules
+
+artifacts
+notebooks
+
+bot.log
+*.log
+
+extension.zip
+tmp_*.js
+tmp_*.html