feat(security): nudge to sign out sessions unused for 3 months (#113)

Sessions of this account not seen for 90+ days (never the current one; a
session with no last-seen time is left alone) get a nudge in the existing
security strip, after the device-security ones and with the same rules
("Not now" snoozes 7 days, gone after 3 dismissals; a snoozed security
nudge no longer hides it): "You have 3 sessions you haven't used in 3
months. Signing them out keeps your account safe if an old device is
lost." [Review]

Review opens Settings -> Devices with those sessions ticked for sign-out
(one confirm, the usual re-auth incl. SSO); they are listed first and
marked "Inactive for 3+ months". OIDC accounts sign out on the
provider's dashboard, so nothing is ticked there.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/features/security-nudge/SecurityBanner.tsx

@@ -23,8 +23,11 @@ import {
   nudgeFor,
   NudgeRecord,
   parseNudgeRecord,
-  shouldShowNudge,
+  pickNudge,
+  staleSessions,
+  staleSessionsText,
 } from '../../utils/securityNudge';
+import { preselectSignOutAtom } from '../../state/staleSessions';
 import { StatusStrip } from '../server-status/ServerStatusBanner';
 
 /** This device's backup connection: undefined until known, then true/false. */
@@ -40,6 +43,35 @@ const useBackupActive = (crypto: CryptoApi): boolean | undefined => {
   return active;
 };
 
+/**
+ * [Gitea #113] Ids of this account's sessions unused for 90+ days. Fetched
+ * once sync has settled, then hourly; [] until known or on error.
+ */
+const useStaleSessionIds = (enabled: boolean): string[] => {
+  const mx = useMatrixClient();
+  const alive = useAlive();
+  const [ids, setIds] = useState<string[]>([]);
+  useEffect(() => {
+    if (!enabled) return undefined;
+    const load = () =>
+      mx
+        .getDevices()
+        .then(({ devices }) => {
+          if (alive())
+            setIds(
+              staleSessions(devices, mx.getDeviceId() ?? undefined, Date.now()).map(
+                (d) => d.device_id,
+              ),
+            );
+        })
+        .catch(() => undefined);
+    load();
+    const t = window.setInterval(load, 60 * 60 * 1000);
+    return () => window.clearInterval(t);
+  }, [mx, enabled, alive]);
+  return ids;
+};
+
 const readRecord = (key: string): NudgeRecord => {
   let raw: string | null = null;
   try {
@@ -84,12 +116,15 @@ function SecurityBannerFor({ crypto }: { crypto: CryptoApi }) {
   let deviceVerified: boolean | undefined;
   if (status === VerificationStatus.Verified) deviceVerified = true;
   else if (status === VerificationStatus.Unverified) deviceVerified = false;
-  const kind = nudgeFor({
+  const securityKind = nudgeFor({
     crossSigning,
     deviceVerified,
     backupOnServer: backupInfo === undefined ? undefined : backupInfo !== null,
     backupActive,
   });
+  const staleIds = useStaleSessionIds(settled);
+  const setPreselect = useSetAtom(preselectSignOutAtom);
+  const kind = pickNudge(securityKind, staleIds.length, record, Date.now());
 
   // One strip at a time: outages, maintenance and a lost connection win.
   // [Gitea #307] Pass what the user dismissed: a dismissed announcement isn't
@@ -97,10 +132,12 @@ function SecurityBannerFor({ crypto }: { crypto: CryptoApi }) {
   const otherStrip =
     syncLost ||
     !!pickBanner(serverStatus, { syncLost, where: 'client', dismissed: new Set(statusDismissed) });
-  if (!settled || !deviceId || !kind || otherStrip || !shouldShowNudge(kind, record, Date.now()))
-    return null;
+  if (!settled || !deviceId || !kind || otherStrip) return null;
 
-  const copy = NUDGE_COPY[kind];
+  const copy =
+    kind === 'stale-sessions'
+      ? { ...NUDGE_COPY[kind], text: staleSessionsText(staleIds.length) }
+      : NUDGE_COPY[kind];
   const dismiss = () => {
     const next = dismissNudge(kind, record, Date.now());
     try {
@@ -113,8 +150,15 @@ function SecurityBannerFor({ crypto }: { crypto: CryptoApi }) {
   return (
     <StatusStrip
       banner={{ key: kind, tone: 'Primary', text: copy.text, dismissable: true }}
-      icon={Icons.ShieldUser}
-      action={{ label: copy.action, onClick: () => requestSettings('devices') }}
+      action={{
+        label: copy.action,
+        onClick: () => {
+          // Review: the Devices page opens with these ticked for sign-out.
+          if (kind === 'stale-sessions') setPreselect(staleIds);
+          requestSettings('devices');
+        },
+      }}
+      icon={kind === 'stale-sessions' ? Icons.Category : Icons.ShieldUser}
       dismissLabel="Not now"
       onDismiss={dismiss}
     />

src/app/features/settings/devices/OtherDevices.tsx

@@ -1,4 +1,5 @@
-import React, { useCallback, useState } from 'react';
+import React, { useCallback, useEffect, useState } from 'react';
+import { useAtom } from 'jotai';
 import { Box, Button, config, Menu, Spinner, Text } from 'folds';
 import { AuthDict, IMyDevice, MatrixError } from 'matrix-js-sdk';
 import { SequenceCard } from '../../../components/sequence-card';
@@ -15,6 +16,8 @@ import { useAuthMetadata } from '../../../hooks/useAuthMetadata';
 import { withSearchParam } from '../../../pages/pathUtils';
 import { useAccountManagementActions } from '../../../hooks/useAccountManagement';
 import { SettingTile } from '../../../components/setting-tile';
+import { preselectSignOutAtom } from '../../../state/staleSessions';
+import { staleSessions } from '../../../utils/securityNudge';
 
 type OtherDevicesProps = {
   devices: IMyDevice[];
@@ -29,6 +32,23 @@ export function OtherDevices({ devices, refreshDeviceList, showVerification }: O
 
   const [deleted, setDeleted] = useState<Set<string>>(new Set());
 
+  // [Gitea #113] The stale-sessions nudge's Review: tick those sessions for
+  // sign-out (one confirm below). OIDC accounts sign out on the provider's
+  // dashboard instead, so nothing is ticked there.
+  const [preselect, setPreselect] = useAtom(preselectSignOutAtom);
+  useEffect(() => {
+    if (preselect.length === 0) return;
+    if (!authMetadata) {
+      const present = new Set(devices.map((d) => d.device_id));
+      setDeleted(new Set(preselect.filter((id) => present.has(id))));
+    }
+    setPreselect([]);
+  }, [preselect, setPreselect, devices, authMetadata]);
+
+  const staleIds = new Set(
+    staleSessions(devices, mx.getDeviceId() ?? undefined, Date.now()).map((d) => d.device_id),
+  );
+
   const handleDashboardOIDC = useCallback(() => {
     const authUrl = authMetadata?.account_management_uri ?? authMetadata?.issuer;
     if (!authUrl) return;
@@ -132,8 +152,20 @@ export function OtherDevices({ devices, refreshDeviceList, showVerification }: O
             />
           </SequenceCard>
         )}
-        {devices
+        {staleIds.size > 0 && (
+          <Text size="T200" priority="300">
+            {staleIds.size === 1
+              ? "1 session hasn't been used in 3 months or more (marked Inactive)."
+              : `${staleIds.size} sessions haven't been used in 3 months or more (marked Inactive).`}{' '}
+            Sign out the ones you no longer use.
+          </Text>
+        )}
+        {[...devices]
+          // [Gitea #113] Inactive (90+ days) sessions first, then most recent.
           .sort((d1, d2) => {
+            const s1 = staleIds.has(d1.device_id) ? 0 : 1;
+            const s2 = staleIds.has(d2.device_id) ? 0 : 1;
+            if (s1 !== s2) return s1 - s2;
             if (!d1.last_seen_ts || !d2.last_seen_ts) return 0;
             return d1.last_seen_ts < d2.last_seen_ts ? 1 : -1;
           })
@@ -145,6 +177,11 @@ export function OtherDevices({ devices, refreshDeviceList, showVerification }: O
               direction="Column"
               gap="400"
             >
+              {staleIds.has(device.device_id) && (
+                <Text size="L400" style={{ color: 'inherit' }}>
+                  Inactive for 3+ months
+                </Text>
+              )}
               <DeviceTile
                 device={device}
                 deleted={deleted.has(device.device_id)}