Add add-page, add-entity, and prototype-review skills

[pglevy]

Summary

Three new project skills for the most repetitive and rule-violation-prone parts of the prototyping workflow, each backed by a deterministic script (in the style of scripts/check-color-palette.js):

• add-page — scaffolds src/pages/<slug>.tsx, registers the route in App.tsx, and links it from home.tsx (scripts/scaffold-page.js). Replaces the manual 4-step process in the README's "Creating New Pages" section.
• add-entity — scaffolds src/db/<entity>.ts with the interface, seed data, and full CRUD functions matching the data-layer convention, already wired through api-config.ts for a future connect-to-appian step (scripts/scaffold-entity.js).
• prototype-review — scans src/pages/ and src/db/ for violations of the four non-negotiable rules (Sailwind imports, UPPERCASE props, Lucide icons not emoji, data in src/db/) plus routing/data-layer conventions, reported by severity (scripts/prototype-review.js).

All three scripts are advisory/deterministic and never block (exit 0), matching the existing check-color-palette.js pattern.

Docs

README.md and AGENTS.md updated to reference the new skills at the relevant workflow steps (Page Development Workflow, Data Layer Convention, Before Declaring Page Complete, Kiro skills table).

Evals

Each skill has evals/evals.json (skill-creator format) with realistic prompts and objective assertions — these are deterministic-script wrappers, so outputs are fully verifiable (file existence, exact route/interface content, pnpm run build exit code) rather than needing subjective grading.

• add-page: basic scaffold request + custom --path route derivation
• add-entity: natural-language field parsing + an irregular-plural regression test (Person → getPeople)
• prototype-review: fixture pages under evals/files/ — one with real violations mixed with a MessageBanner icon="info" false-positive trap, one already clean

Running the evals surfaced a real bug, which is fixed in this PR: scaffold-entity.js was pluralizing Person → getPersons instead of getPeople. Added an irregular-plurals map (person, child, mouse, goose, tooth, foot, woman, man) so common cases are handled automatically.

All 6 evals pass when run against the actual scripts and pnpm run build.

Testing

• pnpm run build passes cleanly
• node scripts/prototype-review.js run against the existing codebase — flags one legitimate finding (a raw <input type="checkbox"> in kanban-board.tsx that could use CheckboxField), no false positives
• Manually ran scaffold-page.js and scaffold-entity.js against several inputs (multi-word names, custom paths, irregular plurals, --no-audit, re-run/--force guard) and reverted test artifacts before committing