Allow-Non-Interlaced-Display

Test builds for the "Respect the current *TV interlace setting" fix
(see the elite-source-code-bbc-micro-disc issue / Stardot thread for details).

Each .ssd is built from the corresponding branch's adaptive-tv-interlace-support
commit. Boot with *TV 0,1 already set for progressive/non-interlaced output,
or leave it alone for the original interlaced behaviour - both are respected.

File	Branch / variant
elite-disc-main-sth.ssd	main (Stairway to Hell variant)
elite-disc-sideways-ram-sram.ssd	main (sideways RAM variant)
elite-disc-flicker-free-sth.ssd	flicker-free
elite-disc-bbc-master-sth.ssd	bbc-master
elite-disc-bbc-master-flicker-free-sth.ssd	bbc-master-flicker-free
elite-disc-music-sth.ssd	music
elite-disc-elite-compendium-bbc-micro.ssd	elite-compendium-bbc-micro
elite-disc-elite-compendium-bbc-master.ssd	elite-compendium-bbc-master

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Updated 20 September 2026 — all eight discs rebuilt with a refinement to the
non-interlace timing constant. The correction from the interlaced timer reload is
48 ticks rather than a flat 64 (i.e. VSCANLO 238 rather than 222), which clears
two small residual artifacts the earlier builds still showed in non-interlace: a
missing pixel at the bottom of the space view's right border, and a faint dotted
white artifact on the left edge of the HUD frame. Confirmed on real BBC Model B
hardware via an OSSC.

Of those 48 ticks, only 32 (half a scan line) is the actual interlace correction.
The remaining 16 clears artifacts the original game could never have cleared: in
interlace sync the 6845 shifts the sync pulse half a scan line on alternate fields,
so any single timer value lands in two different places depending on the field, and
the stock value is necessarily a compromise between competing artifacts. Progressive
output has no such alternation, so both can be cleared at once. The interlaced path
is deliberately left exactly as it was written.