The stem EDA ran on all 14 sections and settled the one parameter that was an
admitted guess. The air shelf sat at +5 dB against a measured 8-16 kHz share of
0.12%, held back because a 320 kbps MP3 puts codec hiss in exactly that band and a
broadband boost cannot tell hiss from hats.

Per stem, mean share of each stem's OWN energy above 8 kHz: drums 0.367%, vocals
0.084%, other 0.033%, bass 0.0%. A 4.4x concentration in drums. Evenly-spread
energy would have meant noise and a shut shelf; concentration means cymbals the
room ate, and opening up is justified by measurement.

HOW FAR is not justified by measurement — that is taste. So --air-gain exists and
the master unit now renders TWO full streaming masters, identical but for the
shelf (+5 and +8), because OPAL already taught us that an effect judged on a clip
is not the same effect judged in place. PLN compares two records tomorrow instead
of ratifying a number I happened to like.

The -9 LUFS "club" target is deliberately dropped, and the reasoning is a
correction to my own earlier conflation of two axes. PLN's "one live club mix"
means the CONTINUOUS set as opposed to the album split — a FORM. Our club variant
is a LOUDNESS. Since no CosmicFest track is cut, the continuous mix simply IS the
master file, so both of his forms were already covered and the -9 render was
optional polish that would have missed anyway (the LRA floor tripped at -10.5 on
the trial). That CPU now buys the A/B, which answers a question he actually has.

Q2, unasked for and worth having: kick presence per track, 40-120 Hz active time
against each track's own p95. Mean 43.4%, against the 59% project_floor_problem
measured for OPAL-26 from real orbit stems. Worst real offenders are #2 There's
Something About Drums at 22.8% and #3 Am i Doing it Right at 33.4%. A stage mic in
a room is a plausible cause on its own, so this is a lead rather than a verdict —
but it is the first time this gig's floor has been measurable at all.

Two things the lens caught that no label would have, both vindicating
feedback_label_and_lens applied to the separator's own names. #14's drums stem is
-84.9 dBFS RMS, essentially empty, which confirms PLN's note that the outro is
"pure dubsiren noise and fun" — so its kick percentage was measuring a noise floor
and reading as a real number. kick_activity is now gated on presence and returns
None with a reason instead, because a percentage of nothing is not a percentage
(presence_is_a_precondition). And #10 PunkAChien's bass stem reads -81.0 dBFS
while its `other` stem is the loudest in the whole table at -26.8: demucs put the
bass INTO other. Anyone reading stem filenames as roles would have concluded
PunkAChien has no bass.

Also fixed the JSON writer, which died on numpy's bool_ after printing every
useful number, and a headline ratio that divided by an epsilon guard when one stem
measured a legitimate 0.000% and announced a 367000x concentration. It now reports
against the runner-up.