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Auto-call is withdrawn — it duplicated DXHunter, which already answers decodes,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

@@ -20,9 +20,15 @@ var (
 	mu        sync.Mutex
 	file      *os.File
 	path      string
+	written   int64    // bytes in the CURRENT file, for the size check in Printf
 	crashFile *os.File // kept open so the runtime can write a crash traceback to it
 )
 
+// maxLogBytes is where the file rolls over, at startup AND while running.
+// A variable, not a constant, so the rotation can be exercised in a test without
+// writing ten megabytes to do it.
+var maxLogBytes int64 = 10 * 1024 * 1024
+
 // Init opens (creates) the log file in dataDir. On rotation we truncate
 // at startup if the file is too big; for now it's a single file, no
 // rolling — the volume is low (a few KB per session).
@@ -47,12 +53,12 @@ func Init(dataDir string) (string, error) {
 			_ = os.Rename(oldLog, logPath)
 		}
 	}
-	// Rotate (don't delete) once the file grows past ~10MB: rename it to
+	// Rotate (don't delete) once the file grows past maxLogBytes: rename it to
 	// opslog.log.1 so the PREVIOUS session's log survives. Deleting it outright used
 	// to erase exactly the diagnostics we needed when a user reported an issue from
 	// the session that just ended. One generation kept — enough, without unbounded growth.
-	if fi, err := os.Stat(logPath); err == nil && fi.Size() > 10*1024*1024 {
-		_ = os.Remove(logPath + ".1")     // drop the older generation
+	if fi, err := os.Stat(logPath); err == nil && fi.Size() > maxLogBytes {
+		_ = os.Remove(logPath + ".1") // drop the older generation
 		if err := os.Rename(logPath, logPath+".1"); err != nil {
 			_ = os.Remove(logPath) // rename failed (locked?) → fall back to the old behaviour
 		}
@@ -96,13 +102,57 @@ func Printf(format string, args ...any) {
 		msg = msg[:len(msg)-1]
 	}
 	if file != nil {
-		fmt.Fprintf(file, "%s %s\n", stamp, msg)
+		n, _ := fmt.Fprintf(file, "%s %s\n", stamp, msg)
+		written += int64(n)
+		rotateIfBigLocked()
 	}
 	// Also dump to stderr in case the binary was launched with a console
 	// attached (wails dev, custom build).
 	fmt.Fprintf(os.Stderr, "%s %s\n", stamp, msg)
 }
 
+// rotateIfBigLocked rolls the file over mid-session once it passes maxLogBytes.
+//
+// The check used to happen at STARTUP only, on the reasonable belief that a
+// session writes a few kilobytes. The CI-V wire trace disproved it: left on for
+// a day it wrote 416 MB, and nothing would have stopped it before the disk did.
+// A log that has to be rotated by quitting the program is not a bound.
+//
+// Same one-generation scheme as the startup rotation, so the previous stretch
+// survives — which is the half an operator usually needs, the part just before
+// the thing they are reporting.
+//
+// Caller holds mu.
+func rotateIfBigLocked() {
+	if written < maxLogBytes || file == nil || path == "" {
+		return
+	}
+	fmt.Fprintf(file, "%s ── log reached %d MB, rotating to %s.1 ──\n",
+		time.Now().Format("15:04:05.000"), maxLogBytes/(1024*1024), filepath.Base(path))
+	_ = file.Close()
+	file = nil
+	_ = os.Remove(path + ".1")
+	if err := os.Rename(path, path+".1"); err != nil {
+		// Rename refused (the file is held open elsewhere, a virus scanner): keep
+		// writing to the old handle rather than losing the log entirely, and try
+		// again in another maxLogBytes rather than on every single line.
+		f, oerr := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
+		if oerr == nil {
+			file = f
+		}
+		written = 0
+		return
+	}
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
+	if err != nil {
+		return // nothing more to be done; the next Printf simply writes nowhere
+	}
+	file = f
+	written = 0
+	fmt.Fprintf(file, "%s ── continued from %s.1 ──\n",
+		time.Now().Format("15:04:05.000"), filepath.Base(path))
+}
+
 // Path returns where the file is so the UI can surface it.
 func Path() string {
 	mu.Lock()
@@ -118,4 +168,19 @@ func Close() {
 		_ = file.Close()
 		file = nil
 	}
+	// The crash file is held open for the whole run so the runtime can dump a
+	// traceback into it without allocating; on the way out it has to be released
+	// like any other handle, or the data directory cannot be moved or removed.
+	if crashFile != nil {
+		// The RUNTIME holds its own duplicate of this handle (SetCrashOutput), so
+		// closing ours releases nothing on Windows — the data directory stays
+		// locked. Hand the runtime a nil first. Anything fatal in the last moments
+		// of shutdown is no longer captured, which is the right trade at a point
+		// where the databases are already closed.
+		_ = debug.SetCrashOutput(nil, debug.CrashOptions{})
+		_ = crashFile.Close()
+		crashFile = nil
+	}
+	path = ""
+	written = 0
 }

internal/applog/rotate_test.go

@@ -0,0 +1,49 @@
+package applog
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// The log has to be bounded WHILE RUNNING, not only at startup. The CI-V wire
+// trace left on for a day wrote 416 MB, and nothing would have stopped it
+// before the disk did.
+func TestRotatesMidSession(t *testing.T) {
+	orig := maxLogBytes
+	maxLogBytes = 8 * 1024 // small, so the test costs milliseconds
+	defer func() { maxLogBytes = orig }()
+
+	dir := t.TempDir()
+	p, err := Init(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer Close()
+
+	line := strings.Repeat("x", 256)
+	for i := 0; i < 100; i++ { // ~25 KB: several times the limit
+		Printf("%s", line)
+	}
+
+	if _, err := os.Stat(p + ".1"); err != nil {
+		t.Fatalf("no previous generation kept: %v", err)
+	}
+	fi, err := os.Stat(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if fi.Size() > maxLogBytes {
+		t.Fatalf("current log is %d bytes, over the %d limit — it did not roll over", fi.Size(), maxLogBytes)
+	}
+	// The new file says where the rest went: a log that starts mid-sentence with
+	// no explanation is how an operator concludes the app lost its history.
+	b, err := os.ReadFile(p)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !strings.Contains(string(b), "continued from "+filepath.Base(p)+".1") {
+		t.Error("the new file does not point at the one it continues")
+	}
+}