feat: panadapter spots that read, a CI-V link that survives, no auto-call

Panadapter spots are now worth reading. The comment carries the spotter, the
entity and the status in DXHunter's own shape — "CQ up 2 [F4BPO] [Franz Josef
Land] [New Slot]" — which needed two things nothing documents: SmartSDR splits
its command line on SPACES, so the words ran together until every space became
non-breaking; and it truncates past ~60 characters, so the cluster's own words
are trimmed first and the three brackets always survive. RBN column padding is
collapsed on the way in, or a preserved run of spaces opened a gap wide enough
to push the rest off screen.

"Already worked" means the CALLSIGN is in the log, not the entity: saying it of
a station never contacted was simply wrong. Each status can also be kept off the
panadapter entirely, and the WSJT-X decode spots obey the same switches — the
palette governs the panadapter, not one of the two things that feed it.

And the radio is no longer hammered: a spot whose frequency, colour and comment
are unchanged is not removed and redrawn. A busy skimmer feed re-spots the same
station every few seconds; one two-minute session sent 2128 adds, 88 of them for
a single callsign, and the display did not move a pixel for any of them.

CI-V, from an IC-7850 that kept killing JTDX: a reply the rig sent to another
controller on the same bus is no longer taken for ours, and a set_ptt, set_freq
or set_mode whose acknowledgement goes missing is verified by reading the rig
back instead of being reported as a failure. WSJT-X and JTDX answer a failed
command with a Rig Control Error and drop the link mid-over — 98 keyings, 6 lost
acknowledgements, 2 dropped connections in one session. The check waits 700 ms,
not the poll's 150: the rig has just failed to answer twice because it was
retuning, and a short probe would fail for the same reason.

Auto-call is withdrawn — it duplicated DXHunter, which already answers decodes,
and two programs deciding that from one shack key over each other. The library
is kept whole and dormant; a guard in App.tsx makes sure a stored preference
cannot key a transmitter whose switch no longer exists.

Also:
  - the log rotates while running, not only at startup: the CI-V trace left on
    wrote 416 MB and nothing would have stopped it before the disk did. Closing
    it now releases the crash file too — the runtime keeps its own duplicate.
  - the interface zoom announces itself, with a badge, a click back to 100% and
    a View menu; Ctrl+wheel and Ctrl+0 always worked and nothing said so.
  - no more elastic bounce, and no swipe-to-navigate out of the app.
  - Edit QSO: your own TX power and the contacted station's extended locator
    were saved and written back with no box to set them.
  - FT decodes: continents are a multiple choice; a compound MSHV message that
    answers two stations in one line is recognised as addressed to you.

frontend/wailsjs/go/models.ts

@@ -3463,6 +3463,7 @@ export namespace main {
 	export class SpotColor {
 	    text: string;
 	    bg?: string;
+	    hide?: boolean;
 	
 	    static createFrom(source: any = {}) {
 	        return new SpotColor(source);
@@ -3472,6 +3473,7 @@ export namespace main {
 	        if ('string' === typeof source) source = JSON.parse(source);
 	        this.text = source["text"];
 	        this.bg = source["bg"];
+	        this.hide = source["hide"];
 	    }
 	}
 	export class SpotColors {