feat: add Jitsi Meet template

[rohitmulani63-ops]

/claim #152
Closes #916

Summary

• Add a Jitsi Meet template for self-hosted video meetings.
• Wire the Jitsi web, Prosody, Jicofo, and JVB services with Dokploy domain routing.
• Add generated auth/component secrets, persistent config/transcript volumes, metadata, and logo.

Validation

• node dedupe-and-sort-meta.js
• npm --prefix build-scripts run validate-template -- --dir ../blueprints/jitsi
• npm --prefix build-scripts run validate-docker-compose -- --file ../blueprints/jitsi/docker-compose.yml
• git diff --check

Notes

• Based on the official docker-jitsi-meet compose structure and Docker deployment guide.
• JVB exposes port 10000 using the template validator-compatible port format.
  Not run: full Docker runtime smoke test, because Docker is unavailable locally.