chore: add EditorConfig for consistent code style

- Configure indentation rules for Python (4 spaces), JS/TSX (2 spaces)
- Set UTF-8 encoding and LF line endings across all files
- Preserve Markdown trailing whitespace

.editorconfig

@@ -5,17 +5,32 @@ root = true
 
 # Unix-style newlines with a newline ending every file
 [*]
+charset = utf-8
 end_of_line = lf
 insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.py]
+indent_size = 4
+indent_style = space
+
+[*.{yml,yaml}]
+indent_style = space
+indent_size = 2
+
+[*.toml]
+indent_size = 4
+indent_style = space
+
+[*.md]
+trim_trailing_whitespace = false
 
 # Matches multiple files with brace expansion notation
 # Set default charset
 [*.{js,tsx}]
-charset = utf-8
 indent_style = space
 indent_size = 2
 
-
 # Matches the exact files either package.json or .travis.yml
 [{package.json,.travis.yml}]
 indent_style = space