Add astro formatter mapping to oxlint editor config

oxfmt doesn't format .astro files, so ultracite init now points VS Code
at the astro-build.astro-vscode extension for astro files under oxlint.

.changeset/oxlint-astro-formatter.md

@@ -0,0 +1,5 @@
+---
+"ultracite": patch
+---
+
+Add an `[astro]` formatter mapping (`astro-build.astro-vscode`) to the oxlint VS Code editor settings generated by `ultracite init`, since oxfmt doesn't format `.astro` files.

.vscode/settings.json

@@ -24,5 +24,8 @@
   "[yaml]": { "editor.defaultFormatter": "oxc.oxc-vscode" },
   "editor.codeActionsOnSave": {
     "source.fixAll.oxc": "explicit"
+  },
+  "[astro]": {
+    "editor.defaultFormatter": "astro-build.astro-vscode"
   }
 }

packages/cli/src/data/editors.ts

@@ -30,6 +30,7 @@ const vscodeBaseConfig = {
 };
 
 // Extension IDs and shared VS Code paths, extracted to avoid repeated literals.
+const ASTRO_FORMATTER = "astro-build.astro-vscode";
 const BIOME_FORMATTER = "biomejs.biome";
 const OXC_FORMATTER = "oxc.oxc-vscode";
 const VSCODE_INSTALL_COMMAND = "code --install-extension";
@@ -63,6 +64,7 @@ export const vscodeBiomeConfig = {
 // Maps https://oxc.rs/docs/guide/usage/formatter.html#supported-languages
 // to https://code.visualstudio.com/docs/languages/identifiers
 export const vscodeOxlintConfig = {
+  "[astro]": { "editor.defaultFormatter": ASTRO_FORMATTER },
   "[css]": { "editor.defaultFormatter": OXC_FORMATTER },
   "[graphql]": { "editor.defaultFormatter": OXC_FORMATTER },
   "[handlebars]": { "editor.defaultFormatter": OXC_FORMATTER },