Add .editorconfig to enforce 2-space indentation

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.vscode/extensions.json

@@ -1,3 +1,3 @@
 {
-  "recommendations": ["Vue.volar"]
+  "recommendations": ["Vue.volar", "EditorConfig.EditorConfig"]
 }