The Missing File modal is one dialog per dead source, cannot be suppressed by a
flag, and sits between a click and a playable rig (#136). On 2026-09-06 it cost a
launch outright — and invisibly, because launch_bin throws app output at
/dev/null: Ardour sat for 13 minutes with 0.08s of CPU and no window at all,
while the only thing that could have said why went to the bit bucket.

So gig-up sweeps the session before opening it, never while it is open (Ardour
saves its in-memory session over the edit on quit and would undo it). Idempotent:
a clean session prints "nothing to do" and writes nothing.

The mount check IS the safety story. --allow-archived overrides the tool's "this
survives elsewhere, restore it instead of dropping the reference" refusal — the
right answer for an accident, the wrong one for deliberate archival, and the only
thing telling those apart is whether the archive is actually there. With the
mirror unmounted the tool cannot distinguish a filed take from a lost one, so it
is never handed the flag. A reference is the last breadcrumb pointing at a take;
dropping one blind turns a restore into a forensics job. Neither branch ever
blocks the gig.

Also writes down what tonight cost, in the cheatsheet where it will be reread at
setup rather than in a log nobody opens mid-gig: Ardour's per-port Incoming MIDI
gates the faders no matter how right everything else is; which of the three LCXL
ports is the correct one and why the other two are wrong; that no-sound-no-
highlight is a stale GHCi (tidalcycles:reboot) and not the rig; and that
boot-superdirt would start a second SuperDirt to fight parvagues-sc for :57120.