https://gitlab.synchro.net/main/sbbs/-/commit/eb01b826ab67bca70b4b0c58
Modified Files:
src/doors/syncdoom/README.md syncdoom.c src/doors/termgfx/README.md gfxgate.h
Log Message:
syncdoom: drop the PPM tier

PPM was the door's first-light encoder, kept afterwards as an opt-in tier
for a SyncTERM without JXL. It cannot earn its place: a frame costs about
a megabyte where sixel costs ~133KB and JXL ~42KB, which is why it was
never auto-selected and was documented as LAN-or-localhost only.

What settles it is that the terminal it existed for does not exist.
SyncTERM advertises sixel and PPM under one capability -- CTerm's "pixel operations" -- and gained sixel at 1189, years before PPM at 1316. Every terminal that can decode a DrawPPM can therefore decode a sixel, at an
eighth of the bytes. A SyncTERM too old for either lands on the text tier
and is playable there. The sibling door reached this conclusion already
and never built a PPM tier; this was the last one.

The auto ladder is unchanged in effect (JXL, else sixel, else text) since
PPM was never in it. What changes: -jxl 0 now means "no JXL" and leaves
the ladder to pick sixel or text, where it used to pin the session to PPM;
a JXL encode failure falls to sixel for the rest of the session rather
than to PPM; and the 320x200 half-size special case goes with it, since it existed only to make PPM's uncompressed bulk survivable.

An existing [video] tier=ppm setting is not silently reinterpreted -- it
says so in the BBS log and falls back to auto.

Also fixes a comment in the shared graphics gate that credited SyncConquer
with an APC PPM tier it never had.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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