feat(cli): improve FTUX to guide users toward AI agent workflow

[jrusso1020]

What

Updates the first-time user experience across CLI output, README, and docs to make the AI-first golden path clear.

Why

The previous FTUX buried the agent workflow in a dim footnote and led with CLI commands. Since the core value prop is AI agents creating videos from HTML, the getting started flow should guide users toward that immediately.

How

CLI output changes

After hyperframes init my-video (non-interactive):

✔ Created my-video/
  compositions
  index.html
  meta.json

Get started:

  1. Open this project with your AI coding agent:
     cd my-video then start Claude Code, Cursor, or your preferred agent
     AI skills are installed — your agent knows how to create and edit compositions.

  2. Preview in the browser:
     cd my-video && npx hyperframes dev

  3. Render to MP4 when ready:
     cd my-video && npx hyperframes render

  Full docs: hyperframes.heygen.com

After hyperframes init (interactive wizard):
Shows a tip after scaffolding:

ℹ Tip: Open this project with Claude Code, Cursor, or your preferred AI agent.
       AI skills are installed — your agent knows how to create and edit compositions.

After hyperframes dev:

◇ Studio running

  Project   my-video
  Studio    http://localhost:3002

  Edit with your AI agent — it has HyperFrames skills installed.
  Changes reload automatically in the studio.

  Press Ctrl+C to stop

Docs changes

• README — Quick Start now leads with opening in an AI agent after init
• Quickstart docs — updated to reflect interactive wizard as default, --non-interactive replaces --human-friendly, edit step mentions AI agent first

Test plan

• npx hyperframes init test-project --non-interactive — shows numbered agent-first steps
• npx hyperframes init test-project (interactive) — shows agent tip after scaffold
• npx hyperframes dev — shows agent hint in server output
• README reads correctly on GitHub
• Quickstart docs render correctly on Mintlify