Refactor compiler around schema-based knowledge units

[nahiyankhan]

Summary

• Refactor Madrigal's core model into a neutral schema-configurable knowledge unit shape with preserved frontmatter, normalized attributes, provenance, and relationships.
• Add schema config for ID/title/kind mapping, path-based fallbacks, kind-required fields, vocabularies, and wikilink extraction/resolution.
• Update loader linting so validate treats strict lint violations as failures while build warns and continues with valid records.
• Keep rule-oriented formats compatible by treating missing enforcement defensively, and update README examples away from design-only assumptions.

Validation

• pnpm run typecheck
• pnpm test
• pre-push hook: pnpm vitest run, pnpm biome check ., pnpm tsc --noEmit

Notes

• No customer-intel-specific terms or brand vocabularies are hardcoded into Madrigal; vocabularies remain consumer-owned config.