fix(test): TestResolveAllowedIP_Timeout is flaky in CI

[Wikid82]

Problem

TestResolveAllowedIP_Timeout in backend/internal/utils/url_testing_security_test.go fails intermittently in CI with Expected timeout error, got nil.

Evidence

• Failed in Backend (Go) on release PR chore(main): release 0.44.3 #1504 (run 37572083310, job 112632740951): FAIL: internal/utils TestResolveAllowedIP_Timeout (0.00s), the only failure out of 10273 tests.
• The same package passed on main (run 37570500238), on the PR fix(security): harden backend consistency checks #1500 branch, and locally, with identical code.
• The test passes context.WithTimeout(ctx, 1*time.Nanosecond) and expects resolveAllowedIP(ctx, "example.com", false) to return an error. Whether the deadline is observed before the resolver returns (cached or hosts-file answer, fast local resolver) is racy, so the result depends on timing and the environment.

Severity

Medium (CI flake). It fails a required check on unrelated branches, and CLAUDE.md forbids deferring failing tests.

Suggested approach

Make it deterministic: cancel the context before the call (cancel() then call), or use a context whose deadline is already in the past, and assert errors.Is(err, context.Canceled) / DeadlineExceeded. Also check that resolveAllowedIP checks ctx.Err() up front so an already-expired context always fails, and make the final assertion a t.Errorf instead of a t.Logf so it actually guards the behavior.