docs: add Sub-Dokumentation section to AGENTS.md and CLAUDE.md for improved documentation structure

- Introduced a new section detailing the Single Source of Truth for various components, linking to their respective CLAUDE.md files.
- Enhanced clarity on documentation organization across different areas of the project.

CLAUDE.md

@@ -1,5 +1,22 @@
 @AGENTS.md
 
+## Sub-Dokumentation
+
+Jeder Ordner hat eine eigene CLAUDE.md als Single Source of Truth:
+
+| Bereich | Dok |
+|---------|-----|
+| Convex Backend | [convex/CLAUDE.md](convex/CLAUDE.md) |
+| Canvas-Engine | [components/canvas/CLAUDE.md](components/canvas/CLAUDE.md) |
+| Design System (ShadCN) | [components/ui/CLAUDE.md](components/ui/CLAUDE.md) |
+| Billing & Credits UI | [components/billing/CLAUDE.md](components/billing/CLAUDE.md) |
+| Dashboard | [components/dashboard/CLAUDE.md](components/dashboard/CLAUDE.md) |
+| Next.js Routing | [app/CLAUDE.md](app/CLAUDE.md) |
+| Utilities & Shared Logic | [lib/CLAUDE.md](lib/CLAUDE.md) |
+| Custom Hooks | [hooks/CLAUDE.md](hooks/CLAUDE.md) |
+
+---
+
 ## Design Context
 
 ### Users