feat: Add CloudWatch Logs browser (M3.7)

[nathanhuh]

Summary

Add CloudWatch Logs browsing with live tail and search capabilities in the TUI.

Details

• List log groups → drill down to log streams
• Live tail mode: poll via FilterLogEvents with auto-scroll
• Time range search with filter pattern support
• Log line syntax highlighting (timestamp, level, message)
• Filter/search within log output

Checklist

• Add CloudWatchLogs service and feature constants in internal/domain/model.go
• Register in catalog via internal/domain/catalog.go
• Implement ListLogGroups(), ListLogStreams(), FilterLogEvents() in internal/services/aws/cloudwatch_logs.go
• Add cloudwatchlogs SDK dependency in go.mod
• Add LogGroupList, LogStreamList, LogViewer screens in internal/app/
• Implement live tail with configurable poll interval
• Add time range picker component
• Add log line syntax highlighting
• Write tests