refactor: move default theme to 'vitepress/theme'

Fixes the case when using a completely custom theme, importing anything
from vitepress causes the entire default theme to be imported too.

BREAKING CHANGE: the default theme is now exposed via 'vitepress/theme',
instead of a named export from 'vitepress'.

src/client/index.ts

@@ -5,7 +5,7 @@
 export type { Router, Route } from './app/router'
 
 // theme types
-export * from './app/theme'
+export type { Theme, EnhanceAppContext } from './app/theme'
 
 // composables
 export { useRouter, useRoute } from './app/router'
@@ -24,6 +24,3 @@ import { ComponentOptions } from 'vue'
 import _Debug from './app/components/Debug.vue'
 const Debug = _Debug as ComponentOptions
 export { Debug }
-
-// default theme
-export { default as DefaultTheme } from './theme-default'

src/node/alias.ts

@@ -38,6 +38,10 @@ export function resolveAliases(
       find: /^vitepress$/,
       replacement: path.join(__dirname, '../client/index')
     },
+    {
+      find: /^vitepress\/theme$/,
+      replacement: path.join(__dirname, '../client/theme-default/index')
+    },
     // alias for local linked development
     { find: /^vitepress\//, replacement: PKG_ROOT + '/' },
     // make sure it always use the same vue dependency that comes with

theme.d.ts

@@ -0,0 +1,3 @@
+// so that users can do `import DefaultTheme from 'vitepress/theme'`
+import DefaultTheme from './dist/client/theme-default/index'
+export default DefaultTheme

types/index.d.ts

@@ -1,5 +1,4 @@
 export * from './shared'
 export * from '../dist/node/index'
-export * from '../dist/client/app/exports'
+export * from '../dist/client/index'
 export * from '../dist/client/theme-default/config'
-export { default as defaultTheme } from '../dist/client/theme-default/index'