docs: align Morse version badges and architecture headings

[krwg]

Summary

• Expand README project badges (P2P, WebRTC, offline-first, Vite, PRs, contributors)
• MESH-PLUS version line synced to 2.0.0 Morse
• ARCHITECTURE headings no longer pin obsolete release numbers

Test plan

• README badge row renders on GitHub
• MESH-PLUS / ARCHITECTURE match app-metadata.json Morse line
• EN/RU Project layout still says 2.0.0 Morse

Closes #56

[krwg]

Notes:

• README badges expanded; EN/RU layout already on 2.0.0 Morse.
• MESH-PLUS and ARCHITECTURE headings aligned with Morse.
• No Co-authored-by / Made with Cursor on the commit.