fix(plugin-inspect): fix connection meta fetch error during dev

Adds a guard to the distDir assignment to prevent the devframe dev server from crashing when the SPA isn't built yet, and configures the vite plugin properly in the SPA's vite config to start the backend dev server.

Author: antfubot

plugins/inspect/src/index.ts

@@ -1,4 +1,5 @@
 import type { DevframeDefinition } from 'devframe/types'
+import { existsSync } from 'node:fs'
 import { fileURLToPath } from 'node:url'
 import { defineDevframe } from 'devframe/types'
 import { setupInspect } from './node/index'
@@ -48,7 +49,7 @@ export function createInspectDevframe(options: InspectDevframeOptions = {}): Dev
     cli: {
       command: id,
       port: options.port ?? 9012,
-      distDir,
+      distDir: existsSync(distDir) ? distDir : undefined,
       // A single-user localhost inspector: skip the trust handshake so
       // the SPA's shared-state subscription initializes without a manual
       // auth round-trip. Hosted adapters (Vite/hub) supply their own

plugins/inspect/src/spa/vite.config.ts

@@ -2,6 +2,7 @@ import { fileURLToPath } from 'node:url'
 import vue from '@vitejs/plugin-vue'
 import { defineConfig } from 'vite'
 import { alias } from '../../../../alias'
+import { inspectVitePlugin } from '../vite'
 
 // The inspector SPA. `base: './'` keeps every asset URL relative so the
 // bundle is mount-path portable — it discovers its runtime base from
@@ -11,7 +12,10 @@ export default defineConfig({
   base: './',
   root: fileURLToPath(new URL('.', import.meta.url)),
   resolve: { alias },
-  plugins: [vue()],
+  plugins: [
+    vue(),
+    inspectVitePlugin({ devMiddleware: true, base: '/' })
+  ],
   build: {
     outDir: fileURLToPath(new URL('../../dist/spa', import.meta.url)),
     emptyOutDir: true,