[FEAT cloudctl] - Add structured logging and verbosity levels

[onuryilmaz]

[FEAT cloudctl] - Add structured logging and verbosity levels

Labels

• feature
• observability
• easy-to-use

Priority

(Medium) I'm annoyed but I'll live

User Story

As a developer or AI agent, I can see structured logs with different verbosity levels, so that I can debug issues more effectively and parse output programmatically.

Description

The current implementation uses standard log.Println which is not structured and lacks levels. Switching to log/slog (modern Go) or a similar library will allow JSON output (AI-friendly) and better debugging with -v/--verbose or --log-level flags.

Acceptance Criteria

• Replace log package usages with log/slog.
• Implement a --log-level flag (debug, info, warn, error).
• Implement a --log-format flag (text, json).
• Ensure sync command logs detailed merging decisions at debug level.

Reference Issues

None