client: include response body in ProtocolSwitch error

[SebTardif]

What this PR does

Fixes #1405.

When exec, portforward, or attach fails because the Kubernetes API server returns a non-101 response (e.g. 403 Forbidden, 404 Pod Not Found), the HTTP response body, which contains a full metav1.Status JSON with message, reason, and details, was discarded. Users saw only:

failed to switch protocol: 403 Forbidden

...instead of the actual error:

pods "my-pod" is forbidden: User "system:serviceaccount:default:my-sa" cannot create resource "pods/exec"

Changes:

• Changed ProtocolSwitch(StatusCode) to ProtocolSwitch { status, body } struct variant
• Made verify_response async to read the response body on failure
• Updated the error Display format to include the body text
• Updated the call site in mod.rs

Closes #1405

AI Disclosure

Developed with AI assistance (Grok by xAI) in a human-in-the-loop workflow. All code reviewed and verified by the human author.

Signed-off-by: Sebastien Tardif sebtardif@ncf.ca

[codecov]

Codecov Report

❌ Patch coverage is 54.54545% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 75.7%. Comparing base (67e4671) to head (b868a0f).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
kube-client/src/client/upgrade.rs	37.5%	5 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #1984     +/-   ##
=======================================
+ Coverage   75.6%   75.7%   +0.2%     
=======================================
  Files         89      89             
  Lines       8666    8751     +85     
=======================================
+ Hits        6544    6622     +78     
- Misses      2122    2129      +7     

Files with missing lines	Coverage Δ
kube-client/src/client/mod.rs	83.0% <100.0%> (+5.4%)	⬆️
kube-client/src/client/upgrade.rs	77.1% <37.5%> (-5.4%)	⬇️

... and 9 files with indirect coverage changes

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