fix(tsconfigs): Add jsx: 'preserve' to the base template

.changeset/slimy-avocados-sniff.md

@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Updates the base `tsconfig.json` preset with `jsx: 'preserve'` in order to fix errors when importing Astro files inside `.js` and `.ts` files.

packages/astro/tsconfigs/base.json

@@ -24,6 +24,8 @@
     // Skip typechecking libraries and .d.ts files
     "skipLibCheck": true,
     // Allow JavaScript files to be imported
-    "allowJs": true
+    "allowJs": true,
+    // Allow JSX files (or files that are internally considered JSX, like Astro files) to be imported inside `.js` and `.ts` files.
+    "jsx": "preserve"
   }
 }