SDP docs: Legend in graphic is missing one term.

[waldmatias]

SDP docs: overview page includes a very useful system arch. layout image at the bottom, and while it even includes a legend, the image is missing the definition (acronym = full term) for "TSS".

[briwylde08]

We're on it!

[ElliotFriend]

The diagram this reported on was replaced during the SDP docs overhaul (#2035, Dec 2025); the current architecture image spells out "Transaction Submission Service" in full, so the missing-legend problem no longer applies. Closing as completed.