Initial portal commit: landing + 9 AI-powered apps

Apps:
- dwg-rooms: extract room numbers from DWG/DXF
- dwg-counting: count symbols in PDF drawings (OpenCV template matching)
- contract-check: review PDF contracts against a checklist (Claude vision + Tesseract OCR fallback)
- email-drafter: bullet notes → polished Czech/English business emails
- invoice-extractor: PDF/image invoice → structured data → Excel
- translator: Czech-first translator across 19 languages with tone control
- vv-check: find inconsistent unit prices across VV sheets in one workbook
- vv-compare: diff original vs new VV files (changes / added / removed)
- feature-request: portal users submit ideas + sample files

Infrastructure:
- LiteLLM gateway with per-app virtual keys + budgets
- Langfuse observability
- Geist font, shared theme, cross-subdomain back link + theme sync via cookie/URL
- Caddy reverse proxy on *.klas.chat

landing/AGENTS.md

@@ -0,0 +1,5 @@
+<!-- BEGIN:nextjs-agent-rules -->
+# This is NOT the Next.js you know
+
+This version has breaking changes — APIs, conventions, and file structure may all differ from your training data. Read the relevant guide in `node_modules/next/dist/docs/` before writing any code. Heed deprecation notices.
+<!-- END:nextjs-agent-rules -->