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.

internal/db/roles.go

@@ -153,6 +153,16 @@ func pruneForeignTables(conn *sql.DB, role Role, label string) {
 	if role != RoleLogbook || conn == nil {
 		return
 	}
+	// Once per database, recorded like a migration.
+	//
+	// The check itself is a COUNT(*) per settings table — twelve round trips,
+	// which is nothing locally and is paid on EVERY open of a remote MySQL
+	// logbook, including every profile switch. There is nothing to find after the
+	// first pass: the role filter means no settings table is ever created in a
+	// logbook again.
+	if _, err := conn.Exec(`INSERT INTO schema_migrations(name) VALUES(?)`, prunedMarker); err != nil {
+		return // already recorded (primary key), or the table is not writable
+	}
 	dropped := 0
 	for _, t := range settingsTables {
 		var n int
@@ -175,6 +185,12 @@ func pruneForeignTables(conn *sql.DB, role Role, label string) {
 	}
 }
 
+// prunedMarker records, in schema_migrations, that a logbook has had its unused
+// settings tables removed. Named like a migration and stored beside them because
+// that is exactly what it is: a one-off schema step, and the applied set is
+// already read in a single query at every open.
+const prunedMarker = "_opslog_pruned_settings_tables"
+
 // quoteIdent quotes one of OUR OWN table names for either dialect. Backticks
 // work in MySQL and in SQLite alike, which is why the migrations use them.
 func quoteIdent(s string) string { return "`" + s + "`" }