style: replace em dashes with colons; add .editorconfig

.editorconfig

@@ -0,0 +1,14 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{dart,yaml,yml,json,md}]
+indent_style = space
+indent_size = 2
+
+[Makefile]
+indent_style = tab

.wiki/Home.md

@@ -25,5 +25,5 @@ print('Sunset:     ${result.sunset.toStringAsFixed(4)} h');
 
 ## Pages
 
-- [API Reference](API-Reference) — Full function and type reference
-- [Architecture](Architecture) — Algorithm design and implementation notes
+- [API Reference](API-Reference): Full function and type reference
+- [Architecture](Architecture): Algorithm design and implementation notes