PDF Change Assurance Benchmark 1.19.0
Adds a deterministic Contents-bound signature coverage control. Both ByteRanges still reach the current file end, but the candidate’s excluded gap no longer exactly matches direct /Contents; the expected result is the generic coverage change plus PFP011.
Validation: 86 tests, reproducible wheel and source builds, Twine checks, and 156/156 process-bound PDFFence checks.