cli: standardize error wrapping with %w (#3040)

[mohamedfawas]

Summary

This PR standardizes error wrapping in the CLI by replacing %v with %w
only in cases where an existing error is being wrapped.

This ensures proper error chaining and enables the use of errors.Is and
errors.As as intended by Go best practices.

---

What was changed

• Updated fmt.Errorf(... %v, err) to fmt.Errorf(... %w, err) in CLI code paths
• Left formatting-only cases (strings, slices, validation errors) unchanged
• No functional changes beyond improved error propagation

---

Why this change

The CLI currently mixes %v and %w for error handling.
Using %w consistently:

• Preserves the original error chain
• Improves debuggability
• Aligns with Go’s recommended error-wrapping patterns

Fixes #3040.

---

Testing

• Changes are limited to error formatting
• No behavior changes were introduced

[codecov]

Codecov Report

❌ Patch coverage is 22.85714% with 108 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@414dcff). Learn more about missing BASE report.
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/container/docker/client.go	10.52%	17 Missing ⚠️
pkg/api/server.go	0.00%	9 Missing ⚠️
pkg/workloads/manager.go	43.75%	9 Missing ⚠️
pkg/container/docker/squid.go	0.00%	8 Missing ⚠️
pkg/runner/retriever/retriever.go	0.00%	7 Missing ⚠️
pkg/runner/runner.go	0.00%	7 Missing ⚠️
...lpha1/virtualmcpcompositetooldefinition_webhook.go	45.45%	6 Missing ⚠️
pkg/client/manager.go	0.00%	6 Missing ⚠️
pkg/container/images/docker.go	0.00%	6 Missing ⚠️
pkg/container/kubernetes/client.go	0.00%	6 Missing ⚠️
... and 13 more

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3094   +/-   ##
=======================================
  Coverage        ?   57.11%           
=======================================
  Files           ?      341           
  Lines           ?    33950           
  Branches        ?        0           
=======================================
  Hits            ?    19390           
  Misses          ?    12951           
  Partials        ?     1609           

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[eleftherias]

Thanks for the PR @mohamedfawas, I noticed some %v remained. I left comments below.

[mohamedfawas]

I ran the failing test locally:

go test ./pkg/workloads/statuses -run TestRuntimeStatusManager_GetWorkload -v

and it passes consistently on my end.

Since this PR only changes error formatting and doesn’t touch workload/status logic, this looks like a CI-only or flaky failure.

Happy to help investigate further or rerun CI if needed—please let me know how you’d like me to proceed.

[eleftherias]

@mohamedfawas I was able to rerun the CI and the test passed. Thanks for your contribution!