fix: stop the viewer crashing on any message with attachments by keeping store selectors referentially stable

src/components/email/AttachmentChips.tsx

@@ -45,11 +45,21 @@ export function AttachmentChips({ email, jmapAccountId, calendarBannerShown, tne
   const t = useLocaleStore((s) => s.t);
   const hideInlineImageAttachments = useSettingsStore((s) => s.hideInlineImageAttachments);
   const mailAttachmentAction = useSettingsStore((s) => s.mailAttachmentAction);
-  const exportOpts = useSettingsStore((s) => ({
-    spaceReplacement: s.exportSpaceReplacement,
-    lowercase: s.exportLowercase,
-    stripDiacritics: s.exportStripDiacritics,
-  }));
+  // Select primitives, not a fresh object: zustand v5 compares snapshots with
+  // Object.is, so a selector returning a new object literal on every call
+  // reports a change on every render - React then re-renders until it gives
+  // up with "Maximum update depth exceeded" (it crashed the whole viewer).
+  const exportSpaceReplacement = useSettingsStore((s) => s.exportSpaceReplacement);
+  const exportLowercase = useSettingsStore((s) => s.exportLowercase);
+  const exportStripDiacritics = useSettingsStore((s) => s.exportStripDiacritics);
+  const exportOpts = React.useMemo(
+    () => ({
+      spaceReplacement: exportSpaceReplacement,
+      lowercase: exportLowercase,
+      stripDiacritics: exportStripDiacritics,
+    }),
+    [exportSpaceReplacement, exportLowercase, exportStripDiacritics],
+  );
 
   const [expanded, setExpanded] = React.useState(false);
   const [busyKey, setBusyKey] = React.useState<string | null>(null);

src/lib/sidebar-apps.ts

@@ -1,3 +1,4 @@
+import React from 'react';
 import { Linking } from 'react-native';
 import { useSettingsStore, type SidebarApp } from '../stores/settings-store';
 
@@ -7,7 +8,11 @@ import { useSettingsStore, type SidebarApp } from '../stores/settings-store';
  * edits them. Mirrors the webmail's navigation-rail filter on `showOnMobile`.
  */
 export function useMobileSidebarApps(): SidebarApp[] {
-  return useSettingsStore((s) => s.sidebarApps.filter((app) => app.showOnMobile));
+  // `.filter()` in the selector would allocate a new array per call, which
+  // zustand v5 reads as a changed snapshot on every render (infinite loop).
+  // Subscribe to the stored array and derive from it.
+  const apps = useSettingsStore((s) => s.sidebarApps);
+  return React.useMemo(() => apps.filter((app) => app.showOnMobile), [apps]);
 }
 
 /**