feat: Ultrabeam over USB, Paper QSL from the awards grid, per-role schemas

Ultrabeam on a serial port never worked, and three faults were stacked so
each hid the next:

  - Stop() did not wait for the poll loop, so a stopped client kept the COM
    port. Every later client then failed with "Serial port busy" — the
    program holding it being OpsLog itself.
  - startUltrabeam tore the old client down CONCURRENTLY with starting the
    new one, and "Test connection" built a second client on a port already
    ours. Harmless over TCP, fatal on a port with one owner.
  - A silent serial port returns (0, nil) and bufio retries that a hundred
    times: a 4 s timeout became ~7 minutes of a frozen poll loop logging
    nothing.

The controller then answered at once. Confirmed on hardware: the USB cable
presents TWO COM ports, only the second reaches the controller, and only at
19200 baud — so the speed is pinned in code (an FTDI cable opens at any
speed, and a wrong one is indistinguishable from a dead controller) and the
port field says which one to pick. The first exchange after each connect is
hex-dumped, which separates silence from a wrong baud from a misread frame.

Databases now carry only the tables their role needs. Every target used to
get the whole migration set, so a shared MySQL logbook grew settings and
station_profiles tables nothing ever wrote to — an operator inspecting the
server could not tell which copy was authoritative. Statements are filtered
by role, unknown tables are kept in both (fail-safe), and existing databases
are cleaned once, dropping only EMPTY tables. Settings → Database gains a
Compact button, since SQLite frees pages inside the file and never shrinks it.

Also:
  - Awards: the callsigns behind a cell open the QSL Manager on Paper QSL,
    searched, ready for the card dates.
  - The record button no longer goes missing after an update: whether manual
    recording is possible is a per-profile question that was asked once, at
    startup, before the profile was known.
  - Alert rules and filter presets confirm that they were saved.
  - Spot clicks on the radio panadapter carry the POTA park into F3.
  - The build gate is re-checked wherever the active callsign can change; it
    ran at startup alone, and a fresh install has no callsign then.

app_gate.go

@@ -18,6 +18,7 @@ var deniedCallHashes = map[string]struct{}{
 	"46fb61e71afb40627cb6493a6a59c9d4d0231ee3cad1a2bf3fcc4cdfce36fabc": {},
 	"d1ae6212ec057f9d5c6f379fb57acedac7c94142c9d49667dc04b2016d03d1b6": {},
 	"0741c9e394b42f43191899105553b47155ddc3026da12b5360701f9c181ff123": {},
+	"ab4926a3a0ab76d41b5b99cd3ad0683584970c341c29427c1dfa4b3c329ce415": {},
 }
 
 // callDenied reports whether a callsign is on deniedCallHashes. The call is