feat(mobile): Skia wave, wave player view, themes and playback settings (M5)

- My Wave is rendered with react-native-skia on the UI thread; physics
  and colour helpers moved to @pipu/core (wave-anim) and shared with web.
- Full-screen player honours ui_prefs.mobile_player (cover / wave).
- Theme switching (dark / light / system) via a theme context and
  useColors() across all screens.
- Profile: theme, wave variant, player view, sound quality sheet
  (Wi-Fi / mobile / downloads), recent-tracks cache clearing on next
  cold start, and a change-password sheet.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/mobile/src/ui/settings.tsx

@@ -0,0 +1,110 @@
+import { ApiError, unwrap } from '@pipu/core';
+import { useState, useSyncExternalStore } from 'react';
+import { useTranslation } from 'react-i18next';
+import { Text, View } from 'react-native';
+
+import { QUALITIES, qualityPrefs, type Quality, type QualityPrefs } from '../lib/prefs';
+import { useSession } from '../lib/session';
+import { useColors } from '../theme';
+import { Button, ErrorBox, Field, Segmented, Sheet, useErrorText } from './kit';
+
+export function useQualityPrefs(): QualityPrefs {
+  return useSyncExternalStore(qualityPrefs.subscribe, qualityPrefs.get);
+}
+
+/** Лист «Качество звука»: Wi-Fi / сотовая / загрузки. */
+export function QualitySheet({ visible, onClose }: { visible: boolean; onClose: () => void }) {
+  const { t } = useTranslation();
+  const colors = useColors();
+  const prefs = useQualityPrefs();
+  const row = (key: keyof QualityPrefs) => (
+    <View style={{ gap: 8 }}>
+      <Text style={{ color: colors.text2, fontSize: 13, fontWeight: '600' }}>{t(`mobile.quality_${key}`)}</Text>
+      <Segmented<Quality>
+        value={prefs[key]}
+        options={QUALITIES.map((q) => ({ value: q, label: t(`mobile.q_${q}`) }))}
+        onChange={(q) => void qualityPrefs.set({ [key]: q })}
+      />
+    </View>
+  );
+  return (
+    <Sheet visible={visible} title={t('mobile.quality')} onClose={onClose}>
+      {row('wifi')}
+      {row('cellular')}
+      {row('download')}
+      <Text style={{ color: colors.text3, fontSize: 12 }}>{t('mobile.quality_hint')}</Text>
+    </Sheet>
+  );
+}
+
+/** Лист смены пароля: после смены сервер выдаёт новую пару токенов, остальные сессии завершаются. */
+export function PasswordSheet({ visible, onClose }: { visible: boolean; onClose: () => void }) {
+  const { t } = useTranslation();
+  const colors = useColors();
+  const session = useSession();
+  const errorText = useErrorText();
+  const [current, setCurrent] = useState('');
+  const [next, setNext] = useState('');
+  const [repeat, setRepeat] = useState('');
+  const [busy, setBusy] = useState(false);
+  const [error, setError] = useState<unknown>(null);
+  const [done, setDone] = useState(false);
+  const mismatch = repeat !== '' && repeat !== next;
+  const fieldErr = (f: string) => (error instanceof ApiError && error.fieldCode(f) ? errorText(error) : undefined);
+
+  const close = () => {
+    setCurrent('');
+    setNext('');
+    setRepeat('');
+    setError(null);
+    setDone(false);
+    onClose();
+  };
+  const submit = async () => {
+    setBusy(true);
+    setError(null);
+    try {
+      const tokens = unwrap(await session.client.POST('/api/v1/me/password', { body: { current_password: current, new_password: next } }));
+      await session.apply(tokens);
+      setDone(true);
+      setCurrent('');
+      setNext('');
+      setRepeat('');
+    } catch (e) {
+      setError(e);
+    } finally {
+      setBusy(false);
+    }
+  };
+
+  return (
+    <Sheet visible={visible} title={t('settings.password')} onClose={close}>
+      {done ? (
+        <>
+          <Text style={{ color: colors.ok }}>{t('settings.password_changed')}</Text>
+          <Button title={t('form.close')} onPress={close} />
+        </>
+      ) : (
+        <>
+          <Field label={t('settings.current_password')} value={current} onChangeText={setCurrent} secure autoComplete="current-password" error={fieldErr('current_password')} />
+          <Field label={t('settings.new_password')} value={next} onChangeText={setNext} secure autoComplete="new-password" error={fieldErr('new_password')} />
+          <Field
+            label={t('settings.repeat_password')}
+            value={repeat}
+            onChangeText={setRepeat}
+            secure
+            autoComplete="new-password"
+            error={mismatch ? t('form.passwords_mismatch') : undefined}
+          />
+          <ErrorBox>{error && !fieldErr('current_password') && !fieldErr('new_password') ? errorText(error) : null}</ErrorBox>
+          <Button
+            title={t('settings.change_password')}
+            busy={busy}
+            disabled={!current || !next || mismatch || repeat === ''}
+            onPress={() => void submit()}
+          />
+        </>
+      )}
+    </Sheet>
+  );
+}