feat: stats — per-band mode split (CW / phone / data) stacked bar chart

Adds Stats.ByBandCategory (per band: CW/phone/data counts, band-plan order) via a
modeCategory() bucketing in stats.go, and a StackedBandBars chart in the Stats
panel showing the split per band with a legend.

frontend/src/components/StatsPanel.tsx

@@ -23,13 +23,14 @@ import { cn } from '@/lib/utils';
 // ─────────────────────────────────────────────────────────────────────────────
 
 type Bucket = { key: string; count: number };
+type BandCat = { band: string; cw: number; phone: number; data: number; total: number };
 type Gap = { start: string; end: string; minutes: number };
 type ContestRun = { id: string; year: number; count: number; start: string; end: string };
 type Stats = {
   total: number; unique_calls: number; entities: number; continents: number;
   first_qso: string; last_qso: string;
   confirmed_lotw: number; confirmed_eqsl: number; confirmed_qsl: number; confirmed_any: number;
-  by_mode: Bucket[]; by_band: Bucket[]; by_operator: Bucket[]; by_station: Bucket[];
+  by_mode: Bucket[]; by_band: Bucket[]; by_band_category: BandCat[]; by_operator: Bucket[]; by_station: Bucket[];
   by_continent: Bucket[]; top_entities: Bucket[]; by_year: Bucket[]; by_month: Bucket[];
   // Period / contest metrics.
   window_start: string; window_end: string; window_hours: number;
@@ -157,6 +158,47 @@ function VBars({ data, empty, height = 150, showValues, colorful }: { data: Buck
   );
 }
 
+// Per-band mode split (CW / phone / data) as stacked vertical bars. The three
+// categories are the subject → categorical colour in a fixed order, matching the
+// mode colours used elsewhere (CW gold, phone green, data blue).
+const BAND_SPLIT = [
+  { key: 'cw', label: 'CW', color: 'var(--chart-3)' },
+  { key: 'phone', label: 'Phone', color: 'var(--chart-2)' },
+  { key: 'data', label: 'Data', color: 'var(--chart-1)' },
+] as const;
+function StackedBandBars({ data, empty, height = 150 }: { data: BandCat[]; empty: string; height?: number }) {
+  if (!data || data.length === 0) return <p className="text-[11px] text-muted-foreground italic py-4 text-center">{empty}</p>;
+  const peak = Math.max(1, ...data.map((d) => d.total));
+  return (
+    <div>
+      <div className="flex items-end gap-[3px] min-w-0" style={{ height }}>
+        {data.map((d) => (
+          <div key={d.band} className="flex-1 min-w-0 flex flex-col items-center justify-end h-full group"
+            title={`${d.band} — CW ${nf(d.cw)} · Phone ${nf(d.phone)} · Data ${nf(d.data)}  (${nf(d.total)})`}>
+            <span className="text-[9px] font-semibold mb-0.5 tabular-nums text-foreground">{nf(d.total)}</span>
+            <div className="w-full flex flex-col justify-end rounded-t-[4px] overflow-hidden"
+              style={{ height: `${Math.max(2, (d.total / peak) * 100)}%` }}>
+              {BAND_SPLIT.map((s) => {
+                const v = d[s.key];
+                if (!v) return null;
+                return <div key={s.key} style={{ flexGrow: v, flexBasis: 0, minHeight: 1, background: s.color }} />;
+              })}
+            </div>
+            <span className="mt-1 h-3 text-[9px] text-muted-foreground w-full text-center whitespace-nowrap">{d.band}</span>
+          </div>
+        ))}
+      </div>
+      <div className="mt-2 flex items-center justify-center gap-3 text-[10px] text-muted-foreground">
+        {BAND_SPLIT.map((s) => (
+          <span key={s.key} className="inline-flex items-center gap-1">
+            <span className="size-2.5 rounded-[3px]" style={{ background: s.color }} /> {s.label}
+          </span>
+        ))}
+      </div>
+    </div>
+  );
+}
+
 // ── Contest rate, stacked by operator ────────────────────────────────────────
 // The categories (the operators) ARE the subject, so this is categorical colour,
 // in the FIXED order the backend sends (busiest first). An operator therefore
@@ -524,7 +566,7 @@ export function StatsPanel() {
       const arr = (v: any) => (Array.isArray(v) ? v : []);
       setStats({
         ...raw,
-        by_mode: arr(raw.by_mode), by_band: arr(raw.by_band), by_operator: arr(raw.by_operator),
+        by_mode: arr(raw.by_mode), by_band: arr(raw.by_band), by_band_category: arr(raw.by_band_category), by_operator: arr(raw.by_operator),
         by_station: arr(raw.by_station), by_continent: arr(raw.by_continent),
         top_entities: arr(raw.top_entities), by_year: arr(raw.by_year), by_month: arr(raw.by_month),
         rate: arr(raw.rate), gaps: arr(raw.gaps),
@@ -740,6 +782,9 @@ export function StatsPanel() {
           <Card title={t('stats.byMode')} accent="var(--chart-2)">
             <HBars data={stats.by_mode} max={8} empty={empty} colorful />
           </Card>
+          <Card title={t('stats.bandSplit')} sub={t('stats.bandSplitSub')} className="lg:col-span-2" accent="var(--chart-3)">
+            <StackedBandBars data={stats.by_band_category} empty={empty} />
+          </Card>
 
           <Card title={t('stats.overTime')} sub={t('stats.overTimeSub')} className="lg:col-span-2" accent="var(--chart-1)">
             <AreaTrend data={stats.by_month} empty={empty} />

frontend/src/lib/i18n.tsx

@@ -60,7 +60,7 @@ const en: Dict = {
   'stats.noData': 'No data', 'stats.charts': 'Charts', 'stats.table': 'Table', 'stats.refresh': 'Refresh',
   'stats.qsos': 'QSOs', 'stats.uniqueCalls': 'Unique callsigns', 'stats.entities': 'Entities',
   'stats.continents': 'Continents', 'stats.confirmed': 'Confirmed',
-  'stats.byBand': 'By band', 'stats.byBandSub': 'In band-plan order, not by size',
+  'stats.byBand': 'By band', 'stats.byBandSub': 'In band-plan order, not by size', 'stats.bandSplit': 'Mode split by band', 'stats.bandSplitSub': 'CW / phone / data per band',
   'stats.byMode': 'By mode', 'stats.byOperator': 'By operator',
   'stats.byOperatorSub': '“—” = logged by the station owner (no OPERATOR set)',
   'stats.byStation': 'By station callsign', 'stats.byContinent': 'By continent',
@@ -374,7 +374,7 @@ const fr: Dict = {
   'stats.noData': 'Aucune donnée', 'stats.charts': 'Graphiques', 'stats.table': 'Tableau', 'stats.refresh': 'Rafraîchir',
   'stats.qsos': 'QSO', 'stats.uniqueCalls': 'Indicatifs uniques', 'stats.entities': 'Entités',
   'stats.continents': 'Continents', 'stats.confirmed': 'Confirmés',
-  'stats.byBand': 'Par bande', 'stats.byBandSub': "Dans l'ordre du plan de bande, pas par taille",
+  'stats.byBand': 'Par bande', 'stats.byBandSub': "Dans l'ordre du plan de bande, pas par taille", 'stats.bandSplit': 'Répartition des modes par bande', 'stats.bandSplitSub': 'CW / phone / data par bande',
   'stats.byMode': 'Par mode', 'stats.byOperator': 'Par opérateur',
   'stats.byOperatorSub': '« — » = loggé par le titulaire (pas d’OPERATOR renseigné)',
   'stats.byStation': 'Par indicatif de station', 'stats.byContinent': 'Par continent',

frontend/wailsjs/go/models.ts

@@ -3411,6 +3411,26 @@ export namespace qslcard {
 
 export namespace qso {
 	
+	export class BandCategory {
+	    band: string;
+	    cw: number;
+	    phone: number;
+	    data: number;
+	    total: number;
+	
+	    static createFrom(source: any = {}) {
+	        return new BandCategory(source);
+	    }
+	
+	    constructor(source: any = {}) {
+	        if ('string' === typeof source) source = JSON.parse(source);
+	        this.band = source["band"];
+	        this.cw = source["cw"];
+	        this.phone = source["phone"];
+	        this.data = source["data"];
+	        this.total = source["total"];
+	    }
+	}
 	export class BandMode {
 	    band: string;
 	    mode: string;
@@ -3900,6 +3920,7 @@ export namespace qso {
 	    confirmed_any: number;
 	    by_mode: Bucket[];
 	    by_band: Bucket[];
+	    by_band_category: BandCategory[];
 	    by_operator: Bucket[];
 	    by_station: Bucket[];
 	    by_continent: Bucket[];
@@ -3939,6 +3960,7 @@ export namespace qso {
 	        this.confirmed_any = source["confirmed_any"];
 	        this.by_mode = this.convertValues(source["by_mode"], Bucket);
 	        this.by_band = this.convertValues(source["by_band"], Bucket);
+	        this.by_band_category = this.convertValues(source["by_band_category"], BandCategory);
 	        this.by_operator = this.convertValues(source["by_operator"], Bucket);
 	        this.by_station = this.convertValues(source["by_station"], Bucket);
 	        this.by_continent = this.convertValues(source["by_continent"], Bucket);

internal/qso/stats.go

@@ -24,6 +24,30 @@ type Bucket struct {
 	Count int    `json:"count"`
 }
 
+// BandCategory is one band's QSO count split by mode category (CW / phone /
+// digital), for the per-band mode-split chart.
+type BandCategory struct {
+	Band  string `json:"band"`
+	CW    int    `json:"cw"`
+	Phone int    `json:"phone"`
+	Data  int    `json:"data"`
+	Total int    `json:"total"`
+}
+
+// modeCategory buckets a mode into "cw", "phone" or "data" (digital). Voice modes
+// (SSB and the digital-voice family) count as phone; CW is CW; everything else is
+// data. Mirrors the frontend's mode colouring.
+func modeCategory(mode string) string {
+	switch strings.ToUpper(strings.TrimSpace(mode)) {
+	case "CW":
+		return "cw"
+	case "SSB", "USB", "LSB", "AM", "FM", "DV", "DIGITALVOICE", "FREEDV", "C4FM", "DSTAR", "FUSION":
+		return "phone"
+	default:
+		return "data"
+	}
+}
+
 // Gap is a stretch with no QSO at all — the off-air periods. In a contest these
 // are the expensive minutes: they are where the score went.
 type Gap struct {
@@ -129,8 +153,9 @@ type Stats struct {
 	ConfirmedAny  int `json:"confirmed_any"`
 
 	// Breakdowns, each sorted most → least (bands keep frequency order).
-	ByMode      []Bucket `json:"by_mode"`
+	ByMode         []Bucket       `json:"by_mode"`
-	ByBand      []Bucket `json:"by_band"`
+	ByBand         []Bucket       `json:"by_band"`
+	ByBandCategory []BandCategory `json:"by_band_category"` // per band: CW / phone / data split
 	ByOperator  []Bucket `json:"by_operator"`
 	ByStation   []Bucket `json:"by_station"` // station_callsign (the call put on the air)
 	ByContinent []Bucket `json:"by_continent"`
@@ -268,6 +293,7 @@ func (r *Repo) Stats(ctx context.Context, from, to time.Time, contestID string,
 		entities   = map[int]struct{}{}
 		modeC      = map[string]int{}
 		bandC      = map[string]int{}
+		bandCat    = map[string]*BandCategory{} // per band: cw/phone/data
 		opC        = map[string]int{}
 		stationC   = map[string]int{}
 		contC      = map[string]int{}
@@ -338,6 +364,20 @@ func (r *Repo) Stats(ctx context.Context, from, to time.Time, contestID string,
 		}
 		if b := strings.ToLower(strings.TrimSpace(band.String)); b != "" {
 			bandC[b]++
+			bc := bandCat[b]
+			if bc == nil {
+				bc = &BandCategory{Band: b}
+				bandCat[b] = bc
+			}
+			switch modeCategory(mode.String) {
+			case "cw":
+				bc.CW++
+			case "phone":
+				bc.Phone++
+			default:
+				bc.Data++
+			}
+			bc.Total++
 		}
 		// op was resolved above (with the operator filter applied).
 		opC[op]++
@@ -414,6 +454,13 @@ func (r *Repo) Stats(ctx context.Context, from, to time.Time, contestID string,
 		}
 		return a < b
 	})
+	// Per-band CW/phone/data split, in the SAME band-plan order as ByBand.
+	s.ByBandCategory = []BandCategory{}
+	for _, b := range s.ByBand {
+		if bc := bandCat[b.Key]; bc != nil {
+			s.ByBandCategory = append(s.ByBandCategory, *bc)
+		}
+	}
 	// The time axis must be CONTINUOUS. Emitting only the months that have QSOs
 	// would place, say, 2012-08 next to 2022-01 as if they were consecutive — the
 	// chart would invent activity that never happened. A gap in the log is real