132 tests: golden-file comparison for all 25 positive fixtures
(17 single-line new-PO + 8 cancellations, Decimal-exact via
parse_float=Decimal), every fail-closed gate reason code covered
(body-level triggers via 17 synthetic adversarial .eml mutations,
candidate-level via direct validate() unit tests), real multi-line
and comment/non-Coupa fallback fixtures, dual line-ending parse
identity, two-path enrich/save parity (site-extractor stream
guard), V10 URL-id corpus sweep, fixture hygiene (ses_auth pass +
scrub-marker leak sweep), and Bedrock dispatch/EMF assertions.
The suite loads handler/template_parser via importlib under
unique module names and binds the handler's bare sibling imports
around exec (tests/conftest.py load_handler gets the same
treatment) -- the WO suite caches bare 'handler'/'template_parser'
names in sys.modules, and bare imports here would silently bind
to the wrong pipeline. moto is imported before the handler so its
botocore stubber hook precedes boto3 session creation (the PO
conftest chain now loads at pytest session start).
Fixtures are scrubbed real S3 samples: transport/auth header
values replaced with same-shape placeholders (structure kept so
ses_auth still passes), per-file digit ciphers, amounts remapped
with sum==total re-established. The .gitignore exception is
scoped to the PO fixtures path only.
Refs: #99
