fix: use bun instead of bunx to run scripts. [⚠️ Potentially dangerous]

[pricci1]

bunx is an alias for bun x, to execute binaries. Docs

Caution

The suggested bunx --bun run dev would download and execute the run package (link). Finger-crossed it is not malicious.

This is the current, wrong, output

> bun create start-app@latest
┌  Let's configure your TanStack Start application
│
◇  What would you like to name your project?
│  my-app
│
◇  Would you like to use Tailwind CSS?
│  Yes
│
◇  Select toolchain
│  Biome
│
◇  What add-ons would you like for your project?
│  none
│
◇  Would you like any examples?
│  none
│
◇  Initialized git repository
│
◇  Installed dependencies
│
▲  Warnings: 
│  TanStack Start is not yet at 1.0 and may change significantly or not be compatible with other add-ons.
│  Migrating to Start might require deleting node_modules and re-installing.
│
└  Your TanStack Start app is ready in 'tanstack-start-rc-tutorial'.

Use the following commands to start your app:
% cd tanstack-start-rc-tutorial
% bunx --bun run dev

Please read README.md for information on testing, styling, adding routes, etc.