Summary

• Converts 4 silent `t.Skip` calls into `t.Fatal` in e2e tests where the skip was masking real regressions.
• Adds a reason string to one legitimate skip in `integration/singlearch` for log readability.
• No production code changed.

Why

Three sites in `test/e2e/golang` and one in `test/e2e/frontend` were silently skipping when their baseline assertion failed. This masks real regressions:

`test/e2e/golang/golang_test.go` (`TestGoBaselineImages`, `TestMultiBinaryImages`, `TestDistrolessImages`)

Each test selects a baseline image specifically because it carries known CVEs. If the baseline scan returns zero vulnerabilities, the test should FAIL loudly — it indicates one of:

• A scanner regression
• A stale Trivy DB
• An upstream image rebuild that resolved the CVEs (test data needs updating)
• A network failure during DB download

Silently skipping made the test green when in fact the test was unable to assert anything.

`test/e2e/frontend/frontend_test.go` (`TestMultiplatformFrontend`)

When every platform's report generation fails, the test was skipping with a hand-wavy "possible disk space or network issue" message. Per-platform failures are already surfaced via `t.Logf` within the loop; if the cumulative result is zero successful reports the failure is real, not flake.

`integration/singlearch/patch_test.go` (legitimate skip, just needs a message)

The skip for local-name images on non-docker buildkit is correct — local-only images can only be tested with docker:// daemon. But the previous `t.Skip()` had no message, making gotestsum output unreadable. Adds a `Skipf` with image ref + current `COPA_BUILDKIT_ADDR`.

Risk

Could turn currently-green CI red if the underlying assumption is wrong (e.g., a baseline image was rebuilt upstream and now has 0 CVEs legitimately). If that happens, the right response is to update the baseline test data, not to re-silence the failure.

Test plan

• `go vet ./test/e2e/golang/... ./test/e2e/frontend/... ./integration/singlearch/...` clean.
• The next CI run on this branch will surface any baseline that's already in the failure mode.

Summary by cubic

Convert silent t.Skip to t.Fatal in baseline-scan checks so real regressions fail fast in CI. Also add a message to one legitimate skip for clearer logs. No production code changes.

• Bug Fixes
  • test/e2e/golang/golang_test.go: Fail with t.Fatalf when a baseline scan returns 0 vulns; includes image context.
  • test/e2e/frontend/frontend_test.go: Fail when zero reports are generated across all platforms.
  • integration/singlearch/patch_test.go: Add t.Skipf message for local-only images on non-docker:// buildkit.

^{Written for commit 66b989e. Summary will update on new commits. Review in cubic}