The framing offers L2 --- wheel sideways, then a height-only resize ---
as the row that witnesses manual horizontal authority on the GPU. It
cannot. Measured before anything was added: the origin survives that
resize with `manual_left_authority` never read anywhere in the
frontend. What preserves it is Q#F6's painted-before policy. `resize`
runs `ensure_caret_painted` only when the caret was painted, and a
caret the user has scrolled off screen is not painted --- so the follow
that would snap the origin back never runs. Whenever the caret IS
painted it is inside the viewport, where `follow_left` returns the
origin it was handed. Either way the latch is unreachable.
What the GPU actually lacked was the other half of clause 3. Nothing
brought the origin DOWN when the maximum fell, for the same reason: the
follow that would is skipped in exactly that state. Measured: scroll to
the right bound at 640px, widen to 1600px, and the origin stayed 960px
past the new maximum --- most of the viewport blank with the text off
its left edge.
`clamp_code_scroll_left` at reshape's tail, beside B5's icon hook and
for the same reason: one point every geometry settle already passes
through. Gated on a non-zero origin, because it scans for the widest
line and most windows are never in this state.
L2 keeps both legs and says plainly that the first is required
behavior, not a witness of the latch. L5's GPU leg makes the stronger
statement available here: the wire stays silent, because on this
frontend moving point means telling the daemon.
One process note. The L5 mutation appeared not to fire; it had failed
to compile. A mutation that does not build produces exactly the output
of a test that passes, and only reading past the grep separated them.
Both were re-run after the mutant compiled: dropping the clamp fires
L2's widening leg, an off-by-one fires its exact bound, and a wire
event on the horizontal leg fires L5.
Still owed: the framing's L2 wording, which promises a witness this
frontend cannot provide.
Gates: fmt; clippy --workspace --all-targets -D warnings; pmacs-gpu
314; --lib 2009; --lib --features crdt 2202; git diff --check.
Levi Neuwirth
ec6444ed25