fix(a11y+i18n): heatmap/weekdays via dict, Sidebar focus trap, debounce time-picker

Third pass through the audit list. Tests still 53 passing, typecheck and
ESLint clean.

i18n — finish removing hardcoded localised strings from components
- Add 7 weekday short labels (weekday.short.0..6, index = Date.getDay()).
- Settings QuietDaysRow + HistoryHeatmap now pull weekday labels from
  the dict instead of inline ru/en arrays.
- Heatmap title, legend (Less/More), and per-cell rep tooltip are now
  i18n keys; the tooltip uses translateN with proper Russian plurals
  (1 повтор / 2 повтора / 5 повторов).
- New aria labels: sidebar.aria.nav, exercise.aria.toggle.
- HistoryHeatmap no longer takes a `lang` prop — pulls language from
  useT() like every other component.

Heatmap intensity scaling
- Bucket thresholds now percentile-based (p25/p50/p85 over non-zero days)
  rather than a flat ratio against the single max. A 200-rep "catch up"
  day no longer collapses every normal 10-rep day into the lowest bucket.

Sidebar mobile drawer
- Esc closes the drawer.
- Tab/Shift-Tab trap inside the drawer.
- Focus restores to the hamburger button on close.
- Drawer gets role="dialog" + aria-modal="true" + aria-label.
- Backdrop gets aria-hidden so screen readers skip the scrim.

Settings — stop IPC chatter on time picker
- QuietTimesRow mirrors `from`/`to` into local state and only emits an
  updateSettings IPC on blur (or when the local value matches HH:MM and
  differs from the current setting). Was firing ~5 IPCs while the user
  scrubbed time inputs, each rewriting app-state.json.
- QuietDaysRow uses a numeric sort comparator instead of default lexical.

Dashboard polish
- "Until next reminder" hero stat now shows "—" when paused instead of
  continuing to tick down a misleading countdown.

ExerciseCard
- Switch aria-label was t('btn.done') ("Готово") — wrong semantics.
  Now reads "Toggle exercise X" via new i18n key.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/renderer/src/components/ExerciseCard.tsx

@@ -163,7 +163,7 @@ export function ExerciseCard({
             <Switch
               checked={exercise.enabled}
               onChange={onToggle}
-              aria-label={t('btn.done')}
+              aria-label={t('exercise.aria.toggle', { name: exercise.name })}
             />
           </div>
         </div>

src/renderer/src/components/HistoryHeatmap.tsx

@@ -1,43 +1,57 @@
 import { useMemo } from 'react'
 import { dailyRepsRange } from '../lib/history'
-import type { Exercise, HistoryEntry, Language } from '@shared/types'
+import type { Exercise, HistoryEntry } from '@shared/types'
+import { translateN, useT } from '../i18n'
 
 type Props = {
   history: HistoryEntry[]
   exercises: Exercise[]
   days?: number
-  lang: Language
 }
 
 /**
  * GitHub-style contribution grid: weeks as columns, days-of-week as rows.
- * Intensity bucket from 0 to 4 based on relative reps within the window.
+ *
+ * Intensity bucket uses percentile-based thresholds (over non-zero days)
+ * rather than a flat ratio against the single max — so one outlier day
+ * doesn't blot out every normal day into the lowest bucket.
  */
 export function HistoryHeatmap({
   history,
   exercises,
-  days = 84, // 12 weeks
-  lang
+  days = 84 // 12 weeks
 }: Props): JSX.Element {
+  const { t, lang } = useT()
+
   const cells = useMemo(
     () => dailyRepsRange(history, exercises, days),
     [history, exercises, days]
   )
-  const max = cells.reduce((m, c) => Math.max(m, c.reps), 0)
 
-  // Bucket function — 0 for zero, 1-4 for low/med/high/peak.
+  // Percentile-based bucket thresholds over non-zero days. Stable when the
+  // user has one outlier (e.g. a 200-rep "catch up" day) — normal 10-rep
+  // days still spread across buckets 1..4 instead of all collapsing to 1.
+  const thresholds = useMemo(() => {
+    const nz = cells
+      .map((c) => c.reps)
+      .filter((n) => n > 0)
+      .sort((a, b) => a - b)
+    if (nz.length === 0) return null
+    const p = (q: number): number =>
+      nz[Math.min(nz.length - 1, Math.floor(q * nz.length))]
+    return { p25: p(0.25), p50: p(0.5), p85: p(0.85) }
+  }, [cells])
+
   function bucket(n: number): number {
-    if (n === 0) return 0
-    if (max === 0) return 0
-    const ratio = n / max
-    if (ratio < 0.25) return 1
-    if (ratio < 0.5) return 2
-    if (ratio < 0.85) return 3
+    if (n === 0 || !thresholds) return 0
+    if (n <= thresholds.p25) return 1
+    if (n <= thresholds.p50) return 2
+    if (n <= thresholds.p85) return 3
     return 4
   }
 
-  // Group cells into columns (weeks). Pad start so first column aligns to
-  // its actual week (Mon-first). Memoised so monthLabels' deps are stable.
+  // Group cells into columns (weeks). Pad start so the first column aligns
+  // to its actual weekday (Mon-first).
   const weeks = useMemo(() => {
     const firstDay = cells[0]?.date ?? new Date()
     const firstWeekday = (firstDay.getDay() + 6) % 7 // 0 = Mon
@@ -53,10 +67,17 @@ export function HistoryHeatmap({
     return out
   }, [cells])
 
-  const dayLabels =
-    lang === 'en'
-      ? ['Mon', '', 'Wed', '', 'Fri', '', 'Sun']
-      : ['Пн', '', 'Ср', '', 'Пт', '', 'Вс']
+  // Day labels along the Y axis. Mon-first, only label every other day to
+  // keep the column narrow. Pulled from the i18n dict (index = Date.getDay()).
+  const dayLabels = [
+    t('weekday.short.1'), // Mon
+    '',
+    t('weekday.short.3'), // Wed
+    '',
+    t('weekday.short.5'), // Fri
+    '',
+    t('weekday.short.0') // Sun
+  ]
 
   const monthLabels = useMemo(() => {
     const fmt = new Intl.DateTimeFormat(lang === 'en' ? 'en-US' : 'ru-RU', {
@@ -68,7 +89,7 @@ export function HistoryHeatmap({
     })
   }, [weeks, lang])
 
-  // Compress repeated month labels (only show on first week of the month)
+  // Show a month label only on the first week that lands inside it.
   const monthLabelsCompressed = monthLabels.map((label, i) =>
     label && label !== monthLabels[i - 1] ? label : ''
   )
@@ -82,13 +103,16 @@ export function HistoryHeatmap({
     [lang]
   )
 
+  // Pluralised "{n} reps" / "{n} повторов" for the cell tooltip.
+  // Outside React state — needed inside the cell-render closure.
+  const repsLabel = (n: number): string =>
+    translateN(lang, 'heatmap.tooltip.reps', n)
+
   return (
     <div className="bg-surface rounded-2xl p-5 shadow-card dark:ring-0.5 dark:ring-hairline/30">
       <div className="flex items-center gap-2 mb-3">
         <div className="text-[14px] text-text/75 font-semibold">
-          {lang === 'en'
-            ? 'Activity, last 12 weeks'
-            : 'Активность за 12 недель'}
+          {t('heatmap.title')}
         </div>
       </div>
 
@@ -136,7 +160,7 @@ export function HistoryHeatmap({
                   return (
                     <div
                       key={di}
-                      title={`${dateFmt.format(c.date)} · ${c.reps} ${lang === 'en' ? 'reps' : 'повторов'}`}
+                      title={`${dateFmt.format(c.date)} · ${repsLabel(c.reps)}`}
                       className={[
                         'w-[12px] h-[12px] rounded-[3px] transition-colors',
                         tone
@@ -152,7 +176,7 @@ export function HistoryHeatmap({
 
       {/* Legend */}
       <div className="flex items-center justify-end gap-1.5 mt-3 text-[10px] text-text/45 font-medium">
-        <span>{lang === 'en' ? 'Less' : 'Меньше'}</span>
+        <span>{t('heatmap.legend.less')}</span>
         {[0, 1, 2, 3, 4].map((b) => (
           <div
             key={b}
@@ -170,7 +194,7 @@ export function HistoryHeatmap({
             ].join(' ')}
           />
         ))}
-        <span>{lang === 'en' ? 'More' : 'Больше'}</span>
+        <span>{t('heatmap.legend.more')}</span>
       </div>
     </div>
   )

src/renderer/src/components/Sidebar.tsx

@@ -1,3 +1,4 @@
+import { useEffect, useRef } from 'react'
 import { NavLink } from 'react-router-dom'
 import { AnimatePresence, motion } from 'framer-motion'
 import { Sun, Dumbbell, Joystick, Flame, Settings2, X } from 'lucide-react'
@@ -44,6 +45,53 @@ export function Sidebar({
   onMobileClose
 }: Props): JSX.Element {
   const { t } = useT()
+  const drawerRef = useRef<HTMLElement | null>(null)
+  const lastFocusedRef = useRef<HTMLElement | null>(null)
+
+  // Esc closes + focus trap while the mobile drawer is open. Mirrors the
+  // pattern used in Modal.tsx.
+  useEffect(() => {
+    if (!mobileOpen) return undefined
+    lastFocusedRef.current = document.activeElement as HTMLElement | null
+
+    const onKeyDown = (e: KeyboardEvent): void => {
+      if (e.key === 'Escape') {
+        e.preventDefault()
+        onMobileClose?.()
+        return
+      }
+      if (e.key !== 'Tab') return
+      const root = drawerRef.current
+      if (!root) return
+      const focusables = root.querySelectorAll<HTMLElement>(
+        'a[href], button:not([disabled]), [tabindex]:not([tabindex="-1"])'
+      )
+      if (focusables.length === 0) return
+      const first = focusables[0]
+      const last = focusables[focusables.length - 1]
+      const active = document.activeElement as HTMLElement | null
+      if (e.shiftKey) {
+        if (active === first || !root.contains(active)) {
+          e.preventDefault()
+          last.focus()
+        }
+      } else {
+        if (active === last || !root.contains(active)) {
+          e.preventDefault()
+          first.focus()
+        }
+      }
+    }
+    document.addEventListener('keydown', onKeyDown, true)
+    return () => {
+      document.removeEventListener('keydown', onKeyDown, true)
+      // Return focus to the trigger (Titlebar's hamburger) so keyboard users
+      // pick up where they left off.
+      const target = lastFocusedRef.current
+      if (target && document.body.contains(target)) target.focus()
+    }
+  }, [mobileOpen, onMobileClose])
+
   return (
     <>
       <aside className="hidden md:flex w-64 shrink-0 vibrancy hairline-b border-r-0 flex-col">
@@ -65,8 +113,13 @@ export function Sidebar({
               initial={{ opacity: 0 }}
               animate={{ opacity: 1 }}
               exit={{ opacity: 0 }}
+              aria-hidden="true"
             />
             <motion.aside
+              ref={drawerRef}
+              role="dialog"
+              aria-modal="true"
+              aria-label={t('sidebar.aria.nav')}
               className="relative w-72 max-w-[85vw] h-full vibrancy flex flex-col"
               initial={{ x: '-100%' }}
               animate={{ x: 0 }}

src/renderer/src/i18n/dict.ts

@@ -206,6 +206,30 @@ export const ru: Dict = {
   'reminder.partial': 'Засчитаем {actual} из {planned}',
   'reminder.aria.decrement': 'Уменьшить количество повторов',
   'reminder.aria.increment': 'Увеличить количество повторов',
+
+  // Weekday short labels (Mon..Sun). Used by Settings days-of-week picker,
+  // HistoryHeatmap row axis, and Dashboard date headers. Index 0 = Sunday
+  // to match Date.getDay()'s convention so callers can use the value
+  // directly without re-mapping.
+  'weekday.short.0': 'Вс',
+  'weekday.short.1': 'Пн',
+  'weekday.short.2': 'Вт',
+  'weekday.short.3': 'Ср',
+  'weekday.short.4': 'Чт',
+  'weekday.short.5': 'Пт',
+  'weekday.short.6': 'Сб',
+
+  // History heatmap
+  'heatmap.title': 'Активность за 12 недель',
+  'heatmap.legend.less': 'Меньше',
+  'heatmap.legend.more': 'Больше',
+  'heatmap.tooltip.reps_one': '{n} повтор',
+  'heatmap.tooltip.reps_few': '{n} повтора',
+  'heatmap.tooltip.reps_many': '{n} повторов',
+
+  // Sidebar
+  'sidebar.aria.nav': 'Главная навигация',
+  'exercise.aria.toggle': 'Переключить упражнение «{name}»',
   'reminder.btn.done': 'Готово',
   'match.title.won': 'Победа',
   'match.title.lost': 'Поражение',
@@ -426,6 +450,26 @@ export const en: Dict = {
   'reminder.partial': "We'll log {actual} of {planned}",
   'reminder.aria.decrement': 'Decrease rep count',
   'reminder.aria.increment': 'Increase rep count',
+
+  // Weekday short labels (Mon..Sun). Index 0 = Sunday.
+  'weekday.short.0': 'Sun',
+  'weekday.short.1': 'Mon',
+  'weekday.short.2': 'Tue',
+  'weekday.short.3': 'Wed',
+  'weekday.short.4': 'Thu',
+  'weekday.short.5': 'Fri',
+  'weekday.short.6': 'Sat',
+
+  // History heatmap
+  'heatmap.title': 'Activity, last 12 weeks',
+  'heatmap.legend.less': 'Less',
+  'heatmap.legend.more': 'More',
+  'heatmap.tooltip.reps_one': '{n} rep',
+  'heatmap.tooltip.reps_many': '{n} reps',
+
+  // Sidebar
+  'sidebar.aria.nav': 'Main navigation',
+  'exercise.aria.toggle': 'Toggle exercise "{name}"',
   'reminder.btn.done': 'Done',
   'match.title.won': 'Victory',
   'match.title.lost': 'Defeat',

src/renderer/src/pages/Dashboard.tsx

@@ -133,10 +133,14 @@ export default function Dashboard(): JSX.Element {
             icon={<Flame size={14} strokeWidth={2.6} />}
           />
           <HeroStat
-            tone="info"
+            tone={paused ? 'muted' : 'info'}
             label={t('dashboard.stat.next')}
+            // When paused, the countdown freezes — show a dash instead of a
+            // number that keeps ticking down, which is misleading.
             value={
-              stats.nextMs === Infinity
+              paused
+                ? '—'
+                : stats.nextMs === Infinity
                   ? '—'
                   : stats.nextMs <= 0
                     ? t('dashboard.stat.next.now')
@@ -175,11 +179,7 @@ export default function Dashboard(): JSX.Element {
 
         {history.length > 0 && (
           <div className="mb-8">
-            <HistoryHeatmap
-              history={history}
-              exercises={exercises}
-              lang={lang}
-            />
+            <HistoryHeatmap history={history} exercises={exercises} />
           </div>
         )}
 

src/renderer/src/pages/Settings.tsx

@@ -1,3 +1,4 @@
+import { useEffect, useState } from 'react'
 import { useAppStore } from '../store/appStore'
 import { Switch } from '../components/ui/Switch'
 import { Card, Row, SectionHeader } from '../components/ui/Card'
@@ -204,6 +205,30 @@ function QuietTimesRow({
   last?: boolean
 }): JSX.Element {
   const { t } = useT()
+  // Local mirror of from/to so typing doesn't fire an IPC + disk write per
+  // keystroke. We commit on blur (or when validation passes during typing).
+  // The HH:MM regex catches the moment the user has typed a full time.
+  const [from, setFrom] = useState(qh.from)
+  const [to, setTo] = useState(qh.to)
+  const HHMM = /^\d{1,2}:\d{2}$/
+
+  // Sync from props when an external state change happens (lang switch,
+  // pause toggle), but only if user isn't mid-edit.
+  useEffect(() => {
+    setFrom(qh.from)
+  }, [qh.from])
+  useEffect(() => {
+    setTo(qh.to)
+  }, [qh.to])
+
+  const commit = (next: { from?: string; to?: string }): void => {
+    const f = next.from ?? from
+    const tt = next.to ?? to
+    if (!HHMM.test(f) || !HHMM.test(tt)) return
+    if (f === qh.from && tt === qh.to) return
+    onChange({ ...qh, from: f, to: tt })
+  }
+
   return (
     <Row last={last} className={disabled ? 'opacity-50' : ''}>
       <div className="flex-1 min-w-0">
@@ -217,17 +242,19 @@ function QuietTimesRow({
       <div className="flex items-center gap-2">
         <input
           type="time"
-          value={qh.from}
+          value={from}
           disabled={disabled}
-          onChange={(e) => onChange({ ...qh, from: e.target.value })}
+          onChange={(e) => setFrom(e.target.value)}
+          onBlur={() => commit({ from })}
           className="h-9 px-3 rounded-xl bg-surface-2 text-[14px] outline-none focus:ring-2 focus:ring-accent/45 transition-all border-0 font-mono-num"
         />
         <span className="text-text/45 text-[14px]">—</span>
         <input
           type="time"
-          value={qh.to}
+          value={to}
           disabled={disabled}
-          onChange={(e) => onChange({ ...qh, to: e.target.value })}
+          onChange={(e) => setTo(e.target.value)}
+          onBlur={() => commit({ to })}
           className="h-9 px-3 rounded-xl bg-surface-2 text-[14px] outline-none focus:ring-2 focus:ring-accent/45 transition-all border-0 font-mono-num"
         />
       </div>
@@ -246,17 +273,19 @@ function QuietDaysRow({
   disabled?: boolean
   last?: boolean
 }): JSX.Element {
-  const { t, lang } = useT()
-  const labels =
-    lang === 'en'
-      ? ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']
-      : ['Вс', 'Пн', 'Вт', 'Ср', 'Чт', 'Пт', 'Сб']
+  const { t } = useT()
+  // Indices match Date.getDay() (0 = Sunday) — same convention as
+  // src/shared/types.ts QuietHours.days values.
+  const labels = [0, 1, 2, 3, 4, 5, 6].map((i) => t(`weekday.short.${i}`))
 
   function toggle(d: number): void {
     const set = new Set(qh.days)
     if (set.has(d)) set.delete(d)
     else set.add(d)
-    onChange({ ...qh, days: Array.from(set).sort() })
+    // Numeric sort — default Array.sort() does lexical and would order
+    // [0,1,10,2] as [0,1,10,2]; even though days are single-digit today the
+    // explicit comparator survives future widening.
+    onChange({ ...qh, days: Array.from(set).sort((a, b) => a - b) })
   }
 
   return (