Fix PR review points: wordlist, images, screenshots restored

- sort -u .wordlist.txt: remove duplicate entries (api's, backend's, etc.)
- Remove 81 orphaned images (66 numbered workshop module shots + workshop/
  subdirectory duplicates + 15 unreferenced root images)
- Restore Kiali, Kafka Console, Kairos, and connectivity-link screenshots
  to observability.md and hub-gateway.md (were dropped during Jekyll→Hugo port)
- Images reduced from 122 to 40 — all 40 are referenced in doc pages
- Add clarifying note to demo-scenario.md: explanatory content only,
  hands-on lab modules remain in showroom-hybrid-mesh-ai repo

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: maximilianoPizarro