feat(mobile): self-update dialog with verified APK download and install (M5)

Checks the server for a newer release at most every 6 hours and on
demand in Profile, shows release notes, downloads the APK with progress,
verifies SHA-256 in 1 MB chunks and hands it to the system installer.
Updates below min_supported cannot be dismissed.

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

apps/mobile/src/ui/UpdateDialog.tsx

@@ -0,0 +1,175 @@
+import { useEffect, useSyncExternalStore } from "react";
+import { useTranslation } from "react-i18next";
+import {
+  AppState,
+  Modal,
+  Pressable,
+  ScrollView,
+  Text,
+  View,
+} from "react-native";
+
+import { useSession, useSessionCtx } from "../lib/session";
+import { updater } from "../lib/update";
+import { colors, radius } from "../theme";
+import { Button } from "./kit";
+
+export function useUpdateState() {
+  return useSyncExternalStore(updater.subscribe, () => updater.state);
+}
+
+/** Проверяет обновления при запуске и возврате в приложение; показывает диалог с «Что нового». */
+export function UpdateDialog() {
+  const { t } = useTranslation();
+  const session = useSession();
+  const { server } = useSessionCtx();
+  const st = useUpdateState();
+
+  useEffect(() => {
+    void updater.check(session);
+    const sub = AppState.addEventListener("change", (s) => {
+      if (s === "active") void updater.check(session);
+    });
+    return () => sub.remove();
+  }, [session]);
+
+  if (
+    st.status === "idle" ||
+    st.status === "checking" ||
+    st.status === "latest"
+  )
+    return null;
+  if (st.status === "available" && st.dismissed) return null;
+
+  const { release, required } = st;
+  const busy = st.status === "downloading" || st.status === "verifying";
+  const action = () => void updater.downloadAndInstall(session, server ?? "");
+
+  return (
+    <Modal
+      transparent
+      animationType="fade"
+      visible
+      onRequestClose={() => updater.dismiss()}
+    >
+      <View
+        style={{
+          flex: 1,
+          backgroundColor: "rgba(0,0,0,0.6)",
+          justifyContent: "center",
+          padding: 24,
+        }}
+      >
+        <View
+          style={{
+            backgroundColor: colors.surface,
+            borderRadius: radius.lg,
+            padding: 20,
+            gap: 12,
+            maxHeight: "80%",
+          }}
+        >
+          <Text style={{ color: colors.text, fontSize: 18, fontWeight: "700" }}>
+            {t("mobile.update_title", { version: release.version })}
+          </Text>
+          {required && (
+            <Text style={{ color: colors.danger }}>
+              {t("mobile.update_required")}
+            </Text>
+          )}
+          {release.notes_md.trim() !== "" && (
+            <ScrollView style={{ maxHeight: 240 }}>
+              <Text style={{ color: colors.text2, lineHeight: 20 }}>
+                {plainNotes(release.notes_md)}
+              </Text>
+            </ScrollView>
+          )}
+          <Text style={{ color: colors.text3, fontSize: 12 }}>
+            {t("mobile.update_size", {
+              size: (release.size / 1048576).toFixed(1),
+            })}
+          </Text>
+
+          {st.status === "downloading" && (
+            <View style={{ gap: 6 }}>
+              <View
+                style={{
+                  height: 4,
+                  borderRadius: 2,
+                  backgroundColor: colors.surface3,
+                }}
+              >
+                <View
+                  style={{
+                    height: 4,
+                    borderRadius: 2,
+                    width: `${Math.round(st.progress * 100)}%`,
+                    backgroundColor: colors.accent2,
+                  }}
+                />
+              </View>
+              <Text style={{ color: colors.text2, fontSize: 12 }}>
+                {t("mobile.update_downloading", {
+                  percent: Math.round(st.progress * 100),
+                })}
+              </Text>
+            </View>
+          )}
+          {st.status === "verifying" && (
+            <Text style={{ color: colors.text2, fontSize: 12 }}>
+              {t("mobile.update_verifying")}
+            </Text>
+          )}
+          {st.status === "error" && (
+            <Text style={{ color: colors.danger }}>
+              {t(
+                st.error === "bad_checksum"
+                  ? "mobile.update_bad_checksum"
+                  : "mobile.update_failed",
+              )}
+            </Text>
+          )}
+          {st.status === "ready" && (
+            <View style={{ gap: 4 }}>
+              <Text style={{ color: colors.text2, fontSize: 12 }}>
+                {t("mobile.update_allow")}
+              </Text>
+              <Pressable
+                onPress={() => void updater.openInstallSettings()}
+                accessibilityRole="link"
+              >
+                <Text style={{ color: colors.accent2, fontWeight: "500" }}>
+                  {t("mobile.update_open_settings")}
+                </Text>
+              </Pressable>
+            </View>
+          )}
+
+          <Button
+            title={t("mobile.update_install")}
+            icon="system-update"
+            busy={busy}
+            onPress={action}
+          />
+          {!required && !busy && (
+            <Button
+              title={t("mobile.update_later")}
+              variant="ghost"
+              onPress={() => updater.dismiss()}
+            />
+          )}
+        </View>
+      </View>
+    </Modal>
+  );
+}
+
+/** Заметки релиза — Markdown; в диалоге показываем текстом без разметки заголовков и выделения. */
+function plainNotes(md: string): string {
+  return md
+    .replace(/^#{1,6}\s*/gm, "")
+    .replace(/\*\*(.+?)\*\*/g, "$1")
+    .replace(/^\s*[-*]\s+/gm, "• ")
+    .replace(/\[(.+?)\]\(.+?\)/g, "$1")
+    .trim();
+}