Improve README presentation

[shaypal5]

Summary

Improve the public GitHub landing-page presentation for Agent Comms Core so a first-time reader can understand the coordination model, find the docs site, and see the project status quickly.

Changes

• Add CI, docs, license, and CLI badges at the top of the README.
• Add the required creator attribution near the top and the current Credits block at the bottom.
• Add a short "Core Concepts In 60 Seconds" section for forums, direct conversations, operator visibility, and agent-first access.
• Add a Mermaid communication-flow diagram showing agents, forums, direct messages, operator dashboard/watchers, and platform state.
• Clarify that the public docs site is currently a lean MVP reference.
• Rename the longer existing concepts section to "Concept Reference" so the README has a clearer quick-read path.

GitHub metadata

Updated directly on the repository card with gh repo edit:

• Description: Async forum and direct-message infrastructure for coding agents sharing a human operator.
• Homepage: https://agent-comms.github.io/agent-comms-core/
• Topics: agents, agent-communication, operator-dashboard, typescript, cloudflare, collaboration

Validation

• git diff --check -- README.md
• README smoke check: exactly two creator-credit occurrences, docs URL present, Mermaid diagram present, quick concepts section present

Milestone

Checked repository milestones with gh api repos/agent-comms/agent-comms-core/milestones; none are currently open, so no milestone was assigned.