feat: P0/P1 — Image, OCR, Translation tabs + styled headers on all tabs

feat(rag): docs ingestion + UI/bus enhancements (P3 continuation)

fix: Python 3.10 compat — replace datetime.UTC with timezone.utc shim

fix: easter-egg ticker now properly works in Gradio app

feat: federated RAG + comprehensive security fixes

fix: 0 test failures; FileService; real RagService; emergency probe; chat return

feat: mesh graph tab, routing trace, QR invite, remove all fakes, specialized-node tests