docs: add Digital Twin Specification for website analysis and reproduction

Adds comprehensive specification document at docs/spec/DIGITAL-TWIN-SPEC.md covering:

- Taxonomy of all website components (design, layout, UI components, pages,
  functionality, data, infrastructure, i18n)
- Ontology: entity types, attributes, relationships
- Topology: DOM, CSS spatial, visual hierarchy, responsive breakpoints
- Media capture: images, video, icons, fonts, documents
- Data collection: text, structured data, URLs, metadata
- Functional specification: behavior, state machines, API contracts
- Design system discovery and analysis
- AI agent architecture (4 phases: Discovery, Analysis, Synthesis, Verification)
- Quality criteria (completeness, accuracy, machine-readability)
- Output format and file structure (c0py-output/ schema)
- Agent contracts, parallelization, error handling

Also updates AGENTS.md and README.md to reference the spec.

Covers 14 major sections with detailed subsections for each component
category found on any modern website or product.

Co-commit with c0py repo on Gitea.

AGENTS.md

@@ -18,6 +18,7 @@
 
 - API-kontrakt: `contracts/openapi.yaml`
 - Schema-versionshantering: semantisk versionering i `packages/types`
+- Digital Twin Spec: `docs/spec/DIGITAL-TWIN-SPEC.md` (fullständig specifikation för webbplats-analys och identisk reproduktion)
 
 ## Fällor
 

README.md

@@ -20,6 +20,7 @@ apps/web/          → Next.js UI — registerhantering, dashboard, visualiserin
 packages/c0py-core → crawling, registry-uppbyggnad, analysmotor
 packages/config    → Zod-validerad env-laddare
 packages/types     → delade TypeScript-typer
+docs/spec/         → Digital Twin Spec (webbplats-analys och reproduktion)
 ```
 
 ## Konsumerade kapabiliteter