vgsp-sema: gate the pool-residue rule on the first translated pool read, not submissions (ISSUE-0002)

r70 c3 proved the submissions gate wrong: the content-rescue path consumes
entry 0 (submissions++) while the pool page is still untranslated (rrc=-2),
then the scanner's pin batch rewinds last_get (SVC_PIN_REWIND) and the entry
is decoded again - this time with cur=134 residue, pay=1, but submissions
already 1, so the residue branch was skipped, the hold branch deferred the
release, and the pending retry dropped it (payload <= cur). The client's
first tracker wait then never completed.

Replace the freshness gate with a per-channel pool_rel_seen flag set on the
first translated pool read (rrc2 == 0), persisted in the pump write-back. The
residue rule now fires exactly on that first read, exactly once per channel
per session.

0 files changed, 0 insertions, 0 deletions