CLI v1.2.0 — New commands, JSON data support, and production hardening

[mononz]

Summary

• Added apialerts init for interactive masked API key setup (TTY-aware)
• Added apialerts config --unset to remove stored API key
• Added --data/-d flag to send for passing arbitrary JSON event data (validated on input)
• send and test now print the destination workspace and channel from the API response instead of swallowing the result
• Integration name changed from "cli" to "apialerts-cli"
• Upgraded SDK dependency to v1.2.0-alpha.4
• Fixed go-version hardcode in all three CI workflows → go-version-file: 'go.mod'
• Replaced all map[string]interface{} with map[string]any
• Added 15 functional tests