fix: resolve vpr ready failures

- Fix unhandled promise in coding-agent example (void operator)
- Fix unhandled promise in cli/dev.ts (void operator)
- Fix ChildProcess.on() type error in cli/process-manager.ts
  (@types/node v25 removed .on() from ChildProcess type)
- Change example build scripts from "vite build" to "vp build"
  (vite resolves to vite-plus-core which has no CLI bin)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

examples/coding-agent/src/App.tsx

@@ -113,7 +113,7 @@ export default defineComponent(() => {
     if (state.value !== "idle") return;
 
     if (key.return) {
-      submit();
+      void submit();
     } else if (key.backspace || key.delete) {
       inputText.value = inputText.value.slice(0, -1);
     } else if (input && !key.ctrl && !key.meta) {