fix: stop intercepting vite as vp and synthesize vpr in task scripts

[fengmk2]

Summary

• Fix: VitePlusCommandHandler was intercepting both vp and vite program names in task scripts. This caused vp run dev to fail with "Invalid vite task command" when a package.json script used bare vite (e.g. "dev": "vite"), because vite is a separate tool, not a vp alias. Now only vp and vpr are intercepted; vite runs verbatim as an external process.
• Feat: vpr commands in task scripts (e.g. "ready": "vpr hello && vpr dev") are now expanded to vp run and synthesized in-session, avoiding unnecessary process spawns.

Test plan

• Added snap test command-run-script-vite-program covering:
  • bare vite, vite -h, vite --version all run verbatim
  • vpr hello synthesized in-session
  • chained vpr hello-vpr && vpr dev-version both synthesized
• All 254 global snap tests pass
• All 22 Rust unit tests pass
• Verified on real reproduction project (vp run dev starts Vite dev server)

Closes #1176