[matthewshober]

Closes #160. A 271 benefit line can apply to a single procedure through EB-13 (C003), which dental payers use for per-CDT-code coinsurance, frequency, age and maximum limits, and which the CAQH CORE eligibility data content rule calls for. The 271 model stopped at EB-12, so those lines read back with no procedure and could not be built without hand-editing the output.

The reader now publishes EB-13 as procedure on each benefit, split into qualifier, code, up to four modifiers and description using the component separator the interchange declares. The 270 reader already decoded the same composite for EQ-02, so that decoder moved to a shared module and both readers use it.

The builder takes a qualifier, code and modifiers and writes them as one composite. It refuses an empty qualifier or code, an empty modifier, and more than four modifiers, because a fifth would land in the description position and an empty one would shift later modifiers on read. It does not emit the description: the CAQH rule and the CMS HETS companion guide only use the qualifier, code and modifier on the 271, and leaving it out of the builder spec keeps it addable later as an optional field.

[NSchatz]

Hey Matthew! Looks good!

[matthewshober]

Thanks for the quick review! I had to fix some formatting errors so I'll need another look.

[NSchatz]

LGTM!

[NSchatz]

I'll cut a release to npm after this is merged!