market bug (hard to describe in a title; see description)

Rookie reports:

> more market bug observations:
>
> * i'm buying tea leaves; there's a listing on the market for 3m., i buy 2, but the third click gives me the 'no longer available' message and then clears tea leaves from the market entirely.
> * using my second account, i put up a few more tea leaves on the market for 10m., this brings the tea listing back up...for a leaf priced 4m. i buy it, then get the 'no longer available' message on the next click.
> * i remove my second account's tea leaves from the market and re-list them for 10m., this creates a listing for 6m tea leaves, of which there appear to be many so i can just buy a bunch
>
> so it seems like it's just aggressively culling items from the market when you buy all listings of a certain price instead of checking if there are any available at a higher price, and you can kinda 'remind' it to look by putting up a new listing

Start by reproducing the reported tea-leaf market sequence: buy all listings at one price, then check whether higher-priced listings remain visible and purchasable. Trace the market listing and purchase flow in the PHP application, since no file or test is named. Done means exhausting one price tier no longer clears valid listings at higher prices or produces an incorrect unavailable message.

Written by the indexing model from the issue text.