PLN: "lets do the migration tbh i want to trust all tracks, lets indeed make
that proper."

The #94 remap had only ever been run against a setlist, so conformance was a
property of having been listed, not of being a track. 685 moves across 148
files, one simultaneous permutation per file, zero clashes.

Button conformance, measured by tools/button-column-audit.py before and after:
**2154/2729 on the orbit's own column (78.9%) -> 2544/2726 (93.3%)**. The
remaining 182 are overflow — an orbit with more controls than the grid gives it,
left in place under a FIXME pointing at gSel, because moving them would put two
orbits on one physical control.

VERIFIED, and this is the part that matters for trusting 703 files:

  * silent-eval --seeded re-run over the WHOLE corpus, 703/703, and diffed
    per-file against the pre-migration baseline in
    docs/2026-09-22-catalog-playability.tsv: **zero verdict changes**. Same 597
    playable, same 85 compile-fail, same 21 silent-orbit, and not one file
    swapped sides. Run at nice 19 / ionice -c3 so it could not preempt the live
    rig mid-rehearsal.
  * re-plan over all 703: 0 moves left.
  * not one CC reference landed in a protected range — 378 refs gained, none of
    them in the Ardour-learned faders (77-84), the A1-A4 level knobs (13-16), or
    the gF1-3 family filters (49-51). Checked as a multiset diff of every CC in
    every changed line, not by reading the tool's promise.
  * every effect BUS slot is byte-identical before and after (`crushbus 41` and
    friends): the tool rewrites quoted `"^NN"` refs only. So the 37 corpus
    pvlint errors, 36 of them PV011 bus-slot sharing, are untouched by this and
    were there before it.

AND THE TOOL STOPPED VANDALISING COMMENTS. The overflow pass expands a hit to
the whole chain segment, so the closing parens of a multi-line step are not left
dangling — and that expansion swallowed comments inside the step. First corpus
run: 18 lines grew a second `--`, three grew a third, and two of the tool's own
FIXME warnings were commented out by the tool that wrote them. A warning the
tool hides on its next run is worse than no warning. Fixed, the corpus reverted,
and re-applied: the two diffs now differ in exactly those lines and nothing else.