feat: wheel over RST; PSK Reporter keeps the band's window

The mouse wheel steps the RST fields — one S-unit on an RST or RS, one
decibel on a digital report, up for a better one — in the entry strip and
in the QSO editor. The dropdown beside them lists the reports worth
having to hand, not all 41 decibels, so the wheel works on the value
rather than walking the list. The listener is native and non-passive:
React attaches onWheel passively, where preventDefault does nothing and
the panel scrolls away under the field being adjusted.

PSK Reporter, whole-band scope: clicking a decode reset the report count
to zero. The window there is the BAND's — every FTx report on it,
filtered by target only when the analysis is drawn — and it was emptied
on every target change, throwing away an hour of evidence at the moment
the operator asked the question it answers. The narrow scope still clears
it: there the window is one station's, and keeping it would answer the
new question with the old station's evidence.

internal/pskrtgt/pskrtgt_test.go

@@ -156,3 +156,26 @@ func TestACrowdedPassbandStillGetsAnAnswer(t *testing.T) {
 		t.Errorf("suggested %d Hz, want the quietest slot around 2400", got)
 	}
 }
+
+// Under the band-wide scope the window is the BAND's, not the target's: it is
+// every FTx report on it, filtered by target only when the analysis is drawn.
+// Clearing it on a target change threw away an hour of accumulated evidence at
+// the exact moment it was worth something — the operator clicking a decode to
+// ask "can he hear me" saw the report count drop to zero.
+func TestBandScopeKeepsItsWindowAcrossATargetChange(t *testing.T) {
+	for _, tc := range []struct {
+		scope Scope
+		keep  bool
+	}{{ScopeBand, true}, {ScopeTarget, false}} {
+		w := &Watcher{cfg: Config{Scope: tc.scope, Logf: func(string, ...any) {}}}
+		w.target, w.mode = "OLD", "FT8"
+		w.spots = []spot{{TxCall: "OLD", RxCall: "F4BPO", at: time.Now()}}
+
+		w.dropWindowOfPreviousTarget()
+		w.target = "NEW"
+
+		if got := len(w.spots) > 0; got != tc.keep {
+			t.Errorf("%s scope: window kept = %v, want %v", tc.scope, got, tc.keep)
+		}
+	}
+}