kitgate blocked the Fred pack and the reason turned out to be much worse than the
flag it raised. Measuring the flagged files: 24 of 153 shipped loops have a peak
between **-104 and -75 dBFS**. They are not quiet. They are digital silence. And
they graded **0.707 to 0.896 — tier A and B**.

The mechanism is that every sub-score in the loop rubric is vacuously perfect on
nothing. The seam between two silences is immaculate. The DC of silence is exactly
zero. Its zero crossings are trivially fine. Its bar length is whatever you cut it
to, so it is bar-exact by construction. Level carries 10% of the composite, so a
silent window scores 0.90 × perfect + 0.10 × nothing ≈ 0.90 and comes out tier A.
The composite had a **degenerate optimum at "no audio at all"**, and the finder,
doing exactly its job, walked into it: `fred_marea_bass` shipped three loops and
all three were silence, from a stem measuring -22 dBFS RMS at 54% activity.

Nothing downstream could catch it either. `_has_dead_bars` compares bars to EACH
OTHER, so it finds a loop that fades out and is blind to one that was never there —
a uniformly silent clip has a perfectly flat bar profile. This is the same trap as
the fade-out loops grading S, one level deeper.

So presence stops being a weighted term and becomes a **precondition**: peak below
`empty_dbfs` ⇒ flag `empty`, grade 0.0, tier D, and the existing MIN_TIER filter
drops it at export. The floor is -60 dBFS, and it is placed rather than tuned: the
pack's peaks run -104…-75 and then jump to -47.1, a **28.4 dB empty gap**, so -60
sits in clean air with nothing near it.

Three details the measurements forced:

* **Presence is measured on the CHANNELS, not the mono sum.** An anti-phase stereo
  pair sums to exact zero; calling that "empty" would both mis-report it and
  suppress the mono-incompatible flag, which is the one useful thing to say about
  it. (Caught by an existing test, which is why it is an existing test.)
* **`near-silent` (RMS < -45) is advisory and now excludes `empty`.** RMS on sparse
  material measures how much silence it contains, not whether it is silent — a hat
  loop peaking at -14.7 reads -48.8 RMS. Two questions, two lenses.
* **`mono-incompatible` no longer fires on silence.** Two independent noise floors
  are uncorrelated, so silence reads as maximally mono-incompatible; four of
  MAREA's flagged vox loops were simply empty.

`kitcheck` asks the presence question too, from its own code path, sharing the one
constant by import so the two lenses cannot drift apart.

Also: restage was not idempotent. Export stages in float and writes PCM_24, so the
peak read back off disk misses the ceiling by a quantization step, measures a hair
hot, and asks to be staged again — by -0.00003 dB, every run, requantizing every
file in the kit each time. `DEAD_BAND_DB = 0.05` (inaudible, four orders of
magnitude above the quantization floor). The dry run now reports 0 of 42 kits,
which is what it was supposed to say in the first place.

7 tests; suite 115 → 119.