[codex] Implement v1.1 quality improvements

[krotname]

Summary

• add ChatServerConfig with bounded client handling, socket timeouts, and explicit busy rejections
• split protocol TEXT payloads from display formatting so data is raw text and sender is the author
• fix GUI/client lifecycle handling, move Swing state updates through the EDT, and update bot command handling
• add architecture docs, README updates, Dependabot grouping, Gradle version catalog, and CI coverage summary

Validation

• .\gradlew.bat spotlessApply check jacocoAllReport --stacktrace
• .\gradlew.bat check --stacktrace
• JaCoCo core coverage after changes: 81.89% line / 69.15% branch

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud