feat: add workstation setup apply flow

[rmanibus]

Summary

Continue RFC 0014 by turning setup workstation into a real onboarding workflow instead of a dry-run-only command.

What changed

• add an explicit apply step for workstation setup plans
• make setup workstation interactive by default
• keep -dry-run as preview-only behavior
• support -yes to skip final confirmation
• persist generated profiles to profiles.yaml
• update tests and docs to reflect the new behavior

Notes

• this slice intentionally reuses the current plan model and naming behavior
• per-folder interactive selection and richer collision handling remain follow-up work
• formal sub-issue attachment under RFC 0014: Epic / Tracking issue for workstation onboarding and profile scaffolding #130 is blocked by token permissions, but this PR addresses Add setup workstation apply flow and confirmation path #196 and continues the RFC 0014: Epic / Tracking issue for workstation onboarding and profile scaffolding #130 onboarding RFC work

Closes #196
Refs #130

[codecov]

Codecov Report

❌ Patch coverage is 53.01205% with 39 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
cmd/cloudstic/cmd_setup.go	31.57%	33 Missing and 6 partials ⚠️

📢 Thoughts on this report? Let us know!