fix: friendly error message when api.ngc.nvidia.com is unreachable

[robobryce]

Summary

• Detect transport-level failures (DNS timeout, dial refused, etc.) during KAS login and token refresh, and render them as a short, actionable message instead of dumping a multi-line stack trace.
• Suppress resty's stderr WARN/ERROR blocks on the auth client unless BREV_DEBUG_HTTP is set — cmderrors already prints a friendly user-facing message and the resty trace is just noise.

Before

brev shell craftax
2026/04/25 11:00:39.237957 WARN RESTY [error]
github.com/brevdev/brev-cli/pkg/store.NewAuthHTTPClient.func1
/go/src/github.com/brevdev/brev-cli/pkg/store/http.go:164
: [error]
github.com/brevdev/brev-cli/pkg/auth.LoginAuth.GetAccessToken
/go/src/github.com/brevdev/brev-cli/pkg/auth/auth.go:33
[…30 more lines…]
: error sending token request: Get "https://api.ngc.nvidia.com/token": dial tcp: lookup api.ngc.nvidia.com on [::1]:53: read udp [::1]:51765->[::1]:53: i/o timeout

After

Could not reach api.ngc.nvidia.com — check your internet connection and try again
Verify you can resolve api.ngc.nvidia.com and that no firewall or proxy is blocking it. If the host is reachable, the service may be temporarily unavailable.

Implementation

• pkg/errors/errors.go — new NetworkError type plus IsNetworkError, HostFromURLError, WrapNetworkError helpers.
• pkg/auth/kas.go — wrap client.Do failures in MakeLoginCall and retrieveIDToken with WrapNetworkError, deriving the host from BaseURL.
• pkg/cmd/cmderrors/cmderrors.go — handle *NetworkError in the type switch: render in yellow with directive, skip Sentry reporting.
• pkg/store/http.go — install a silent resty logger on the auth HTTP client when not in debug mode.

Test plan

• go test ./pkg/errors/... — 13 tests pass (table-driven IsNetworkError, host extraction, wrap behavior, message content, Unwrap/errors.Is chain, real httptest.Server integration, pkgerrors.Cause survival through WrapAndTrace).
• go test ./pkg/auth/... — 12 tests pass including new TestMakeLoginCall_NetworkError, TestRetrieveIDToken_NetworkError, TestRetrieveIDToken_NonNetworkErrorUnchanged, and Test_hostFromURL.
• go test ./pkg/cmd/cmderrors/... — captures stderr to assert friendly rendering with no [error]/github.com/brevdev/... lines, and that plain errors still render through.
• go test ./pkg/store/... and go vet ./... clean across the entire module.

🤖 Generated with Claude Code

[brycelelbach]

@patelspratik I think this is a better user facing diagnostic, but not sure, thoughts?

[codecov]

Codecov Report

❌ Patch coverage is 87.83784% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 18.72%. Comparing base (9e0e34b) to head (ebb6a68).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/errors/errors.go	88.00%	4 Missing and 2 partials ⚠️
pkg/store/http.go	66.66%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #367      +/-   ##
==========================================
+ Coverage   18.18%   18.72%   +0.54%     
==========================================
  Files         140      140              
  Lines       18684    18763      +79     
==========================================
+ Hits         3398     3514     +116     
+ Misses      14912    14865      -47     
- Partials      374      384      +10     

Flag	Coverage Δ
Linux	18.72% <87.83%> (+0.54%)	⬆️

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