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Auto-call is withdrawn — it duplicated DXHunter, which already answers decodes,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.

internal/cat/flex.go

@@ -74,6 +74,15 @@ type Flex struct {
 	// end up outside the new window — see ZoomPan.
 	panWindow map[string]panView
 
+	// spotSig is what each live spot LOOKS like, and when it was drawn. A
+	// callsign spotted again with the same frequency, colour and comment does not
+	// need to be removed and re-added: the panadapter would not change by one
+	// pixel, and a busy RBN feed re-spots the same station every few seconds. One
+	// two-minute session sent 2 128 adds and 1 634 removes, 88 of them for a
+	// single callsign — see SendSpot.
+	spotSig  map[string]string
+	spotSent map[string]time.Time
+
 	spotByCall map[string]int // callsign → live spot index, so re-spotting a call replaces its old spot (WSJT decodes re-fire every cycle)
 	sentCmds   map[int]string // seq → command text, so an R<seq> error names the command
 
@@ -205,7 +214,7 @@ func NewFlex(host string, port int, spotsEnabled bool) *Flex {
 	return &Flex{
 		host: strings.TrimSpace(host), port: port,
 		slices: map[int]*flexSlice{}, spotsEnabled: spotsEnabled,
-		spotIdx: map[int]bool{}, pendingSpot: map[int]string{}, pendingSpotMode: map[int]string{}, spotCall: map[int]string{}, spotMode: map[int]string{}, spotFreq: map[int]int64{}, pendingSpotFreq: map[int]int64{}, panWindow: map[string]panView{}, spotByCall: map[string]int{}, pendingSplit: map[int]bool{},
+		spotIdx: map[int]bool{}, pendingSpot: map[int]string{}, pendingSpotMode: map[int]string{}, spotCall: map[int]string{}, spotMode: map[int]string{}, spotFreq: map[int]int64{}, pendingSpotFreq: map[int]int64{}, panWindow: map[string]panView{}, spotSig: map[string]string{}, spotSent: map[string]time.Time{}, spotByCall: map[string]int{}, pendingSplit: map[int]bool{},
 		meterMeta: map[int]meterInfo{}, meterVal: map[int]float64{}, meterSub: map[int]bool{},
 		sentCmds: map[int]string{}, txSetAt: map[string]time.Time{},
 		pinnedSlice: -1,
@@ -859,6 +868,13 @@ func (f *Flex) handleStatus(payload string) {
 				}
 				f.mu.Lock()
 				if removed {
+					// The radio expired or dropped this spot: forget what it looked
+					// like, or the next identical spot would be skipped as "already
+					// drawn" and the station would never come back.
+					if c, ok := f.spotCall[idx]; ok {
+						delete(f.spotSig, strings.ToUpper(c))
+						delete(f.spotSent, strings.ToUpper(c))
+					}
 					delete(f.spotIdx, idx)
 					delete(f.spotCall, idx)
 					delete(f.spotMode, idx)
@@ -1390,7 +1406,22 @@ func (f *Flex) SendSpot(s SpotInfo) error {
 	// and Go mutexes aren't reentrant (calling send while locked deadlocks the
 	// whole Flex goroutine → the radio drops OFFLINE).
 	upperCall := strings.ToUpper(s.Callsign)
+	// Unchanged and still fresh → leave it alone.
+	//
+	// Refreshed once past half its lifetime, so a long-lived spot still gets its
+	// timer wound on and never quietly expires off the panadapter; anything that
+	// actually differs (a new frequency, a status that has changed colour, a
+	// different comment) is redrawn at once.
+	sig := fmt.Sprintf("%d|%s|%s|%s|%s", s.FreqHz, s.Mode, s.Color, s.BackgroundColor, s.Comment)
 	f.mu.Lock()
+	if prev, ok := f.spotSig[upperCall]; ok && prev == sig {
+		if at, ok := f.spotSent[upperCall]; ok && time.Since(at) < time.Duration(life)*time.Second/2 {
+			f.mu.Unlock()
+			return nil
+		}
+	}
+	f.spotSig[upperCall] = sig
+	f.spotSent[upperCall] = time.Now()
 	old, hadOld := f.spotByCall[upperCall]
 	if hadOld {
 		delete(f.spotByCall, upperCall)
@@ -1464,6 +1495,8 @@ func (f *Flex) ClearSpots() error {
 	f.spotCall = map[int]string{}
 	f.spotMode = map[int]string{}
 	f.spotFreq = map[int]int64{}
+	f.spotSig = map[string]string{}
+	f.spotSent = map[string]time.Time{}
 	f.spotByCall = map[string]int{}
 	connected := f.conn != nil
 	f.mu.Unlock()