feat(stats): redesign session timeline and clean up vocabulary tab

- Replace cumulative line chart with activity-focused area chart showing per-interval new words
- Add total words as a blue line on a secondary right Y-axis
- Add pause shaded regions, seek markers, and card mined markers with numeric x-axis for reliable rendering
- Add clickable header logo with proper aspect ratio
- Remove unused "Hide particles & single kana" checkbox from vocabulary tab

stats/src/App.tsx

@@ -30,7 +30,14 @@ export function App() {
   return (
     <div className="min-h-screen flex flex-col bg-ctp-base">
       <header className="px-4 pt-3 pb-0">
-        <h1 className="text-lg font-semibold text-ctp-text mb-2">SubMiner Stats</h1>
+        <button
+          type="button"
+          onClick={() => handleTabChange('overview')}
+          className="flex items-center gap-2 mb-2 hover:opacity-80 transition-opacity"
+        >
+          <img src="/favicon.png" alt="" className="h-6 object-contain" />
+          <h1 className="text-lg font-semibold text-ctp-text">SubMiner Stats</h1>
+        </button>
         <TabBar activeTab={activeTab} onTabChange={handleTabChange} />
       </header>
       <main className="flex-1 overflow-y-auto p-4">

stats/src/components/sessions/SessionDetail.tsx

@@ -1,10 +1,11 @@
 import {
-  LineChart, Line, XAxis, YAxis, Tooltip, ResponsiveContainer,
-  ReferenceLine,
+  ComposedChart, Area, Line, XAxis, YAxis, Tooltip, ResponsiveContainer,
+  ReferenceArea, ReferenceLine,
 } from 'recharts';
 import { useSessionDetail } from '../../hooks/useSessions';
 import { CHART_THEME } from '../../lib/chart-theme';
 import { EventType } from '../../types/stats';
+import type { SessionEvent } from '../../types/stats';
 
 interface SessionDetailProps {
   sessionId: number;
@@ -27,10 +28,29 @@ function formatTime(ms: number): string {
   });
 }
 
-const EVENT_COLORS: Partial<Record<number, { color: string; label: string }>> = {
-  [EventType.CARD_MINED]: { color: '#a6da95', label: 'Card mined' },
-  [EventType.PAUSE_START]: { color: '#f5a97f', label: 'Pause' },
-};
+interface PauseRegion { startMs: number; endMs: number }
+
+function buildPauseRegions(events: SessionEvent[]): PauseRegion[] {
+  const regions: PauseRegion[] = [];
+  const starts = events.filter((e) => e.eventType === EventType.PAUSE_START);
+  const ends = events.filter((e) => e.eventType === EventType.PAUSE_END);
+
+  for (const start of starts) {
+    const end = ends.find((e) => e.tsMs > start.tsMs);
+    regions.push({
+      startMs: start.tsMs,
+      endMs: end ? end.tsMs : start.tsMs + 2000,
+    });
+  }
+  return regions;
+}
+
+interface ChartPoint {
+  tsMs: number;
+  activity: number;
+  totalWords: number;
+  paused: boolean;
+}
 
 export function SessionDetail({ sessionId, cardsMined }: SessionDetailProps) {
   const { timeline, events, loading, error } = useSessionDetail(sessionId);
@@ -38,84 +58,188 @@ export function SessionDetail({ sessionId, cardsMined }: SessionDetailProps) {
   if (loading) return <div className="text-ctp-overlay2 text-xs p-2">Loading timeline...</div>;
   if (error) return <div className="text-ctp-red text-xs p-2">Error: {error}</div>;
 
-  const chartData = [...timeline]
-    .reverse()
-    .map((t) => ({
+  const sorted = [...timeline].reverse();
+  const pauseRegions = buildPauseRegions(events);
+
+  const chartData: ChartPoint[] = sorted.map((t, i) => {
+    const prevWords = i > 0 ? sorted[i - 1]!.wordsSeen : 0;
+    const delta = Math.max(0, t.wordsSeen - prevWords);
+    const paused = pauseRegions.some((r) => t.sampleMs >= r.startMs && t.sampleMs <= r.endMs);
+    return {
       tsMs: t.sampleMs,
-      time: formatTime(t.sampleMs),
-      words: t.wordsSeen,
-      cards: t.cardsMined,
-    }));
+      activity: delta,
+      totalWords: t.wordsSeen,
+      paused,
+    };
+  });
+
+  const cardEvents = events.filter((e) => e.eventType === EventType.CARD_MINED);
+  const seekEvents = events.filter(
+    (e) => e.eventType === EventType.SEEK_FORWARD || e.eventType === EventType.SEEK_BACKWARD,
+  );
 
   const pauseCount = events.filter((e) => e.eventType === EventType.PAUSE_START).length;
-  const seekCount = events.filter(
-    (e) => e.eventType === EventType.SEEK_FORWARD || e.eventType === EventType.SEEK_BACKWARD,
-  ).length;
-  const cardEventCount = events.filter((e) => e.eventType === EventType.CARD_MINED).length;
+  const seekCount = seekEvents.length;
+  const cardEventCount = cardEvents.length;
 
-  const markerEvents = events.filter((e) => EVENT_COLORS[e.eventType]);
+  const maxActivity = Math.max(...chartData.map((d) => d.activity), 1);
+  const yMax = Math.ceil(maxActivity * 1.3);
+
+  const tsMin = chartData.length > 0 ? chartData[0]!.tsMs : 0;
+  const tsMax = chartData.length > 0 ? chartData[chartData.length - 1]!.tsMs : 0;
 
   return (
     <div className="bg-ctp-mantle border border-ctp-surface1 rounded-lg p-3 mt-1 space-y-3">
       {chartData.length > 0 && (
-        <ResponsiveContainer width="100%" height={120}>
-          <LineChart data={chartData}>
+        <ResponsiveContainer width="100%" height={150}>
+          <ComposedChart data={chartData} barCategoryGap={0} barGap={0}>
+            <defs>
+              <linearGradient id={`actGrad-${sessionId}`} x1="0" y1="0" x2="0" y2="1">
+                <stop offset="0%" stopColor="#c6a0f6" stopOpacity={0.5} />
+                <stop offset="100%" stopColor="#c6a0f6" stopOpacity={0.05} />
+              </linearGradient>
+            </defs>
             <XAxis
-              dataKey="time"
+              dataKey="tsMs"
+              type="number"
+              domain={[tsMin, tsMax]}
               tick={{ fontSize: 9, fill: CHART_THEME.tick }}
               axisLine={false}
               tickLine={false}
+              tickFormatter={formatTime}
+              interval="preserveStartEnd"
             />
             <YAxis
+              yAxisId="left"
               tick={{ fontSize: 9, fill: CHART_THEME.tick }}
               axisLine={false}
               tickLine={false}
-              width={28}
+              width={24}
+              domain={[0, yMax]}
+              allowDecimals={false}
             />
-            <Tooltip contentStyle={tooltipStyle} />
-            <Line dataKey="words" stroke="#c6a0f6" strokeWidth={1.5} dot={false} name="Words" />
-            <Line dataKey="cards" stroke="#a6da95" strokeWidth={1.5} dot={false} name="Cards" />
-            {markerEvents.map((e, i) => {
-              const cfg = EVENT_COLORS[e.eventType]!;
-              const matchIdx = chartData.findIndex((d) => d.tsMs >= e.tsMs);
-              const x = matchIdx >= 0 ? chartData[matchIdx]!.time : null;
-              if (!x) return null;
-              return (
-                <ReferenceLine
-                  key={`${e.eventType}-${i}`}
-                  x={x}
-                  stroke={cfg.color}
+            <YAxis
+              yAxisId="right"
+              orientation="right"
+              tick={{ fontSize: 9, fill: CHART_THEME.tick }}
+              axisLine={false}
+              tickLine={false}
+              width={30}
+              allowDecimals={false}
+            />
+            <Tooltip
+              contentStyle={tooltipStyle}
+              labelFormatter={formatTime}
+              formatter={(value: number, name: string) => {
+                if (name === 'New words') return [`${value}`, 'New words'];
+                if (name === 'Total words') return [`${value}`, 'Total words'];
+                return [value, name];
+              }}
+            />
+
+            {/* Pause shaded regions */}
+            {pauseRegions.map((r, i) => (
+              <ReferenceArea
+                key={`pause-${i}`}
+                yAxisId="left"
+                x1={r.startMs}
+                x2={r.endMs}
+                y1={0}
+                y2={yMax}
+                fill="#f5a97f"
+                fillOpacity={0.15}
+                stroke="#f5a97f"
+                strokeOpacity={0.4}
                 strokeDasharray="3 3"
-                  strokeOpacity={0.6}
-                  label=""
+                strokeWidth={1}
               />
-              );
-            })}
-          </LineChart>
+            ))}
+
+            {/* Seek markers */}
+            {seekEvents.map((e, i) => (
+              <ReferenceLine
+                key={`seek-${i}`}
+                yAxisId="left"
+                x={e.tsMs}
+                stroke="#91d7e3"
+                strokeWidth={1}
+                strokeDasharray="3 4"
+                strokeOpacity={0.5}
+              />
+            ))}
+
+            {/* Card mined markers */}
+            {cardEvents.map((e, i) => (
+              <ReferenceLine
+                key={`card-${i}`}
+                yAxisId="left"
+                x={e.tsMs}
+                stroke="#a6da95"
+                strokeWidth={2}
+                strokeOpacity={0.8}
+                label={{
+                  value: '⛏',
+                  position: 'top',
+                  fill: '#a6da95',
+                  fontSize: 14,
+                  fontWeight: 700,
+                }}
+              />
+            ))}
+
+            <Area
+              yAxisId="left"
+              dataKey="activity"
+              stroke="#c6a0f6"
+              strokeWidth={1.5}
+              fill={`url(#actGrad-${sessionId})`}
+              name="New words"
+              dot={false}
+              activeDot={{ r: 3, fill: '#c6a0f6', stroke: '#1e2030', strokeWidth: 1 }}
+              type="monotone"
+              isAnimationActive={false}
+            />
+            <Line
+              yAxisId="right"
+              dataKey="totalWords"
+              stroke="#8aadf4"
+              strokeWidth={1.5}
+              dot={false}
+              activeDot={{ r: 3, fill: '#8aadf4', stroke: '#1e2030', strokeWidth: 1 }}
+              name="Total words"
+              type="monotone"
+              isAnimationActive={false}
+            />
+          </ComposedChart>
         </ResponsiveContainer>
       )}
 
-      <div className="flex flex-wrap gap-4 text-xs text-ctp-subtext0">
-        <span>{pauseCount} pause{pauseCount !== 1 ? 's' : ''}</span>
-        <span>{seekCount} seek{seekCount !== 1 ? 's' : ''}</span>
-        <span className="text-ctp-green">{Math.max(cardEventCount, cardsMined)} card{Math.max(cardEventCount, cardsMined) !== 1 ? 's' : ''} mined</span>
-      </div>
-
-      {markerEvents.length > 0 && (
-        <div className="flex flex-wrap gap-3 text-[10px]">
-          {Object.entries(EVENT_COLORS).map(([type, cfg]) => {
-            if (!cfg) return null;
-            const count = markerEvents.filter((e) => e.eventType === Number(type)).length;
-            if (count === 0) return null;
-            return (
-              <span key={type} className="flex items-center gap-1">
-                <span className="inline-block w-2.5 h-0.5 rounded" style={{ background: cfg.color }} />
-                <span className="text-ctp-overlay2">{cfg.label} ({count})</span>
+      <div className="flex flex-wrap items-center gap-4 text-[11px]">
+        <span className="flex items-center gap-1.5">
+          <span className="inline-block w-3 h-2 rounded-sm" style={{ background: 'linear-gradient(to bottom, rgba(198,160,246,0.5), rgba(198,160,246,0.05))' }} />
+          <span className="text-ctp-overlay2">New words</span>
+        </span>
+        <span className="flex items-center gap-1.5">
+          <span className="inline-block w-3 h-0.5 rounded" style={{ background: '#8aadf4' }} />
+          <span className="text-ctp-overlay2">Total words</span>
+        </span>
+        {pauseCount > 0 && (
+          <span className="flex items-center gap-1.5">
+            <span className="inline-block w-3 h-2 rounded-sm" style={{ background: 'rgba(245,169,127,0.2)', border: '1px solid rgba(245,169,127,0.5)' }} />
+            <span className="text-ctp-overlay2">{pauseCount} pause{pauseCount !== 1 ? 's' : ''}</span>
           </span>
-            );
-          })}
-        </div>
         )}
+        {seekCount > 0 && (
+          <span className="flex items-center gap-1.5">
+            <span className="inline-block w-3 h-0.5 rounded" style={{ background: '#91d7e3', opacity: 0.7 }} />
+            <span className="text-ctp-overlay2">{seekCount} seek{seekCount !== 1 ? 's' : ''}</span>
+          </span>
+        )}
+        <span className="flex items-center gap-1.5">
+          <span className="text-[12px]">⛏</span>
+          <span className="text-ctp-green">{Math.max(cardEventCount, cardsMined)} card{Math.max(cardEventCount, cardsMined) !== 1 ? 's' : ''} mined</span>
+        </span>
+      </div>
     </div>
   );
 }

stats/src/components/vocabulary/VocabularyTab.tsx

@@ -1,4 +1,4 @@
-import { useMemo, useState } from 'react';
+import { useState } from 'react';
 import { useVocabulary } from '../../hooks/useVocabulary';
 import { StatCard } from '../layout/StatCard';
 import { WordList } from './WordList';
@@ -7,7 +7,6 @@ import { KanjiDetailPanel } from './KanjiDetailPanel';
 import { formatNumber } from '../../lib/formatters';
 import { TrendChart } from '../trends/TrendChart';
 import { buildVocabularySummary } from '../../lib/dashboard-data';
-import { isFilterable } from './pos-helpers';
 import type { KanjiEntry, VocabularyEntry } from '../../types/stats';
 
 interface VocabularyTabProps {
@@ -18,18 +17,12 @@ interface VocabularyTabProps {
 export function VocabularyTab({ onNavigateToAnime, onOpenWordDetail }: VocabularyTabProps) {
   const { words, kanji, loading, error } = useVocabulary();
   const [selectedKanjiId, setSelectedKanjiId] = useState<number | null>(null);
-  const [hideParticles, setHideParticles] = useState(true);
   const [search, setSearch] = useState('');
 
-  const filteredWords = useMemo(
-    () => hideParticles ? words.filter(w => !isFilterable(w)) : words,
-    [words, hideParticles],
-  );
-
   if (loading) return <div className="text-ctp-overlay2 p-4">Loading...</div>;
   if (error) return <div className="text-ctp-red p-4">Error: {error}</div>;
 
-  const summary = buildVocabularySummary(filteredWords, kanji);
+  const summary = buildVocabularySummary(words, kanji);
 
   const handleSelectWord = (entry: VocabularyEntry): void => {
     onOpenWordDetail?.(entry.wordId);
@@ -52,15 +45,6 @@ export function VocabularyTab({ onNavigateToAnime, onOpenWordDetail }: Vocabular
       </div>
 
       <div className="flex flex-wrap items-center gap-3">
-        <label className="flex items-center gap-2 text-xs text-ctp-subtext0 select-none cursor-pointer">
-          <input
-            type="checkbox"
-            checked={hideParticles}
-            onChange={(e) => setHideParticles(e.target.checked)}
-            className="rounded border-ctp-surface2 bg-ctp-surface1 text-ctp-blue focus:ring-ctp-blue"
-          />
-          Hide particles & single kana
-        </label>
         <input
           type="text"
           value={search}
@@ -86,7 +70,7 @@ export function VocabularyTab({ onNavigateToAnime, onOpenWordDetail }: Vocabular
       </div>
 
       <WordList
-        words={filteredWords}
+        words={words}
         selectedKey={null}
         onSelectWord={handleSelectWord}
         search={search}