chore: add editorconfig and gitignore

.editorconfig

@@ -0,0 +1,18 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2
+
+[*.cs]
+indent_size = 4
+
+[*.{csproj,props,targets,slnx}]
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false

.gitignore

@@ -0,0 +1,27 @@
+# OS
+.DS_Store
+Thumbs.db
+
+# IDE
+.vs/
+.idea/
+.vscode/*
+!.vscode/extensions.json
+*.user
+
+# .NET
+bin/
+obj/
+
+# Node
+node_modules/
+dist/
+*.local
+
+# Client build output copied into backend
+backend/wwwroot/
+
+# Env / secrets
+.env
+.env.*
+!.env.example