feat(stovepipe): add Queue.LastGreenRequestID in Stovepipe Queue

[roychying]

Why?

The record stage advances the queue's last-green bookmark, and that bookmark must only ever move forward. entity.Queue today carries LastGreenURI but no record of which request established it, so there is nothing to compare a candidate against — a late-arriving delivery for an older request could regress the bookmark to a stale commit, which process would then hand to build as an incremental baseline.

Adding the owning request id gives the guard something to compare, using the same ingest-order comparison (CompareRequestID) that ingest and process already use for coalescing.

What?

• entity.Queue gains LastGreenRequestID, paired with the existing LastGreenURI.
• The MySQL queueStore threads it through Create, Get, and Update.
• schema/queue.sql gains last_green_request_id VARCHAR(255) NOT NULL DEFAULT '', so existing rows read back as "bookmark never set" and the first green outcome adopts unconditionally.

Test Plan

make gazelle, make build, make test - all clean

Issue