feat: convert from mdbook to Grav format

- Rename src/ to pages/
- Add Grav frontmatter to markdown files
- Create numbered folder structure
- Remove mdbook-specific files

Migration from mdbook to Grav CMS.

pages/02.internal-price-book/default.md

@@ -0,0 +1,20 @@
+---
+title: 'KNEL — Internal Price Book (Draft)'
+menu: 'KNEL — Internal Price Book (Draft)'
+---
+
+# KNEL — Internal Price Book (Draft)
+
+Intent
+- Nominal, simple rates; accountability over precision; revisit after CPA review and revenue.
+
+Model (proposed)
+- Base infra absorbed by KNEL initially; per‑LLC flat recharge starts only when revenue is material (TBD).
+
+SKUs (initial)
+- CLD-APP-SLOT — Cloudron app slot (per deployed app)
+- OIDC-IDP — OIDC identity provider (per LLC)
+- GIT-ORG — Gitea organization
+- MAT-PROP — Matomo property (site ID)
+- DOC-SEAT — Documenso seats (bundle)
+- RED-PROJ — Redmine project (per LLC)