Fix extractor truncation (bound each HTTP message by Content-Length): userMassInfo
(8 KB) and purchasegroup responses are now complete in the committed corpus, not
cut at 4 KB. Document the userMassInfo envelope contract (target shape for a future
full-Rust migration; needs the clubAbbr/established account triad Core lacks).
Rebuilds the primary-capture corpus lost to .gitignore (Known Issues #200): 10
real-client requests + 12 responses captured during the post-P1 staging A/B on a
real FIFA 17 client, sanitised (SID/authCode/deviceId/MAC/tokens redacted; raw pcap
withheld). Documents the account/sync, empty-My-Packs 65534 sentinel, and userMassInfo
contracts, incl. the finding that account/sync is coupled to Python active-profile
selection (so it can't migrate standalone from the userMassInfo hybrid).
funman300