Supersedes the parse gate in 26b0819f. The off-thread read, the claim token, the
teardown ordering and its bounded wait all stand — only what happens in the gap
changes.
26b0819f held every report back until the calibration read came home, so a pad
that stalled on EP0 could feel dead for up to the link's 250 ms timeout: no
buttons, no sticks, nothing. Reports are now forwarded immediately and their
motion scaled by the nominal calibration until the real one lands.
That gap is exactly the behaviour that shipped before f6de620f — acceleration
~18% short, gyro unscaled — for about a millisecond. Nobody can feel that. A
controller that ignores a button press for a quarter of a second is not in the
same category, and it is the only one of the two a user would ever report.
It is also the safer of the two conservatisms available here. The rejected third
option, forwarding motion as zeroes until the real numbers arrive, would have the
host read a still pad as being in free fall — a lie about the physical world
rather than an imprecision about it. The nominal constants are merely a slightly
wrong scale.
The token is more load-bearing under this, not less. With a gate, an unpublished
calibration meant "parse nothing"; now it means "scale nominally", so begin()
clearing the previous pad's value is the whole reason a re-claim falls back to
the nominal constants instead of silently inheriting factory numbers belonging to
a different unit — which are, in general, further off than nominal. The fallback
therefore lives in the hand-off itself (MotionCalHandoff.effective) rather than
as an elvis at the call site: restoring the gate now means changing the type's
API, not deleting three characters in onReport.
The tests moved with the contract. They assert the nominal calibration is what is
in effect during the gap, rather than merely that the slot is empty — an empty
slot is now compatible with either behaviour, so asserting on it would have let
a regression pass. Added the case the change exists for: the same raw report,
parsed either side of publication, forwards identical buttons and sticks while
its gyro and acceleration convert differently. Mutation-checked three ways —
dropping the nominal fallback fails all five cases, dropping begin's clear fails
the inheritance case, dropping the token check fails three.
Gate: `:kit:compileDebugKotlin`, `:kit:testDebugUnitTest` and
`:app:compileDebugKotlin` green on a forced clean rerun, 62 cases across the
module, 0 failed, with the five hand-off cases read back out of the JUnit XML.
The on-glass re-verification f6de620f owes is still owed and unchanged.
enricobuehler
8e8d30202c