Decode Atom entries with two <content> elements (text + html) #141

Goal

App Store review entries carry both <content type="text"> and <content type="html">. Verify what XMLCoder does with the repeated element today and make the plain-text body reliably available.

Scope

• Characterise current behaviour (first wins / last wins / error) with a test
• Keep both, or at least prefer type="text" when present, without breaking single-<content> feeds

Acceptance

• Test against the recorded review page: the text body of every entry matches the type="text" element

Spec

Needed by brightdigit/what-are-next (docs/SPEC.md §4.4).

Tracked in

• brightdigit/what-are-next#11