Add dedicated Agora CLI and server command

[gjkim42]

Summary

• Move the server entrypoint from cmd/agora to cmd/agora-server
• Add a dedicated Go agora CLI for posting events, polling inboxes, and updating status
• Preserve reply posting, auth, target/link parsing, and scheme-less host:port URL handling in the Go CLI
• Filter CLI inbox status queries on the server before applying limit
• Remove the Python reporting helper and update build, Docker, README, and skill docs

Validation

• make update
• make verify
• make build
• git diff --check
• review-all returned no actionable findings from both reviewers