Improve Agent setup, verification and capability contract guidance

[erickkkyt]

Changes

• Make the public Skill an actionable secure setup and Search → Inspect → Run guide.
• Correct fabricated references and the API status endpoint in the legacy package.
• Document partial Inspect schemas and require actual official contracts before spending.
• Add executable read-only walkthrough tests, including authentication and empty-search failures.

Validation

• npm run verify: passed (10 tests and package build).
• Scoped secret-pattern review and diff whitespace checks passed.
• No API keys or paid task calls included.