web: scaffold Vue 3 + Vite app (create-vue, lean options)

Verbatim output of 'npm create vue@latest web -- --ts --vitest
--eslint --prettier' so this commit shows exactly what the official
scaffold generates; our own changes come separately. Lean per the
agreed choices: no Router/Pinia until a second page or shared state
exists. node_modules is ignored via the scaffold's own web/.gitignore.

web/.editorconfig

@@ -0,0 +1,8 @@
+[*.{js,jsx,mjs,cjs,ts,tsx,mts,cts,vue,css,scss,sass,less,styl}]
+charset = utf-8
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+end_of_line = lf
+max_line_length = 100