Add the Taskbean site delivery agent team

[nicholasdbrady]

PR #3 established the site's canonical Copilot harness, but the agent-team and anti-slop work was completed after that PR merged. This follow-up adds the specialized delivery team without changing the shipped site.

What changed

• Adds one user-invokable Site Director as the sole contact for product shaping, design, implementation, audit, and release coordination.
• Adds four hidden specialists with independent seams:
  • Product Shaper for product truth, positioning, scope, acceptance criteria, and PRODUCT.md.
  • Experience Designer for Impeccable-led visual direction, critique, DESIGN.md, and product-specific anti-slop contracts.
  • Frontend Engineer for production HTML/CSS/JavaScript, responsive implementation, and detector remediation.
  • Release Auditor for independent accessibility, performance, responsive, implementation-integrity, and anti-slop verdicts.
• Requires user approval at product-positioning changes, visual-world replacement, and merge.
• Requires separate release-readiness and anti-slop PASS verdicts for every UI-changing branch.
• Adds routing eval seeds and a dependency-free validator that enforces exactly one user-invokable agent, hidden-specialist availability, read-only audit boundaries, and required anti-slop contracts.
• Runs the agent-team validator in the existing site validation workflow.

Anti-slop boundary

The Impeccable detector is required evidence, not an automatic verdict. The independent auditor verifies findings in rendered context, blocks confirmed non-advisory slop, documents false positives or deliberate exceptions, and manually checks generic composition and synthetic copy patterns that static rules cannot detect.

Validation

• node scripts/validate-agent-team.mjs
• YAML parse of all five .agent.md profiles
• node scripts/validate-site.mjs
• git diff --check