Per QA review of PR #794:
1. hub_test.go TestNewHub_WithAccessChecker: `called` was set but never
read (unused variable → go vet failure). Added assertion that checks
`called` is true after verifying the access checker was invoked.
2. bundle_helpers_test.go TestSplitLines_Empty: `want` was declared as
[]string{""} but only len(want) was used — the actual content was
never compared. Fixed to assert len(got)==1 && got[0]=="", which
validates the correct split behavior for an empty string.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>