fix: sync code not transferring identity when encryption enabled

_getAllData() was reading raw storage which contains encrypted blobs
when at-rest encryption is enabled. The sync code export would send
{ _ssLocalEncrypted: true, data: <blob> } instead of actual identity
data. The importing browser couldn't use these blobs.

Fixed _getAllData() to use Storage._readSecure() which decrypts
transparently. Fixed _applyData() to use Storage._writeSecure()
so imported data gets encrypted on the receiving end.

Also: hide the Auto-Sync Folder section entirely in browsers that
don't support File System Access API (Firefox, Brave, Safari)
instead of showing a broken-looking error message.

https://claude.ai/code/session_01SWSwDfMVij53bCTNSCLMwn

src/lib/sync.js

@@ -791,25 +791,41 @@ const SilentSendSync = {
   // ----------------------------------------------------------------
 
   async _getAllData() {
-    const result = await api.storage.local.get(null);
+    // Use dynamic import to avoid circular dependency
+    const StorageModule = (await import('./storage.js')).default;
+    const identity = await StorageModule._readSecure('ss_identity');
+    const mappings = await StorageModule._readSecure('ss_mappings');
+    const settings = await StorageModule._readSecure('ss_settings');
+    const result = await api.storage.local.get('ss_lastModified');
     return {
       version: '1',
       lastModified: result.ss_lastModified || Date.now(),
-      identity: result.ss_identity || {},
-      mappings: result.ss_mappings || [],
-      settings: result.ss_settings || {},
+      identity: identity || {},
+      mappings: mappings || [],
+      settings: settings || {},
     };
   },
 
   async _applyData(data, source = 'unknown') {
-    const toSet = {
+    const StorageModule = (await import('./storage.js')).default;
+
+    // Write through Storage module so data gets encrypted if at-rest
+    // encryption is enabled
+    if (data.identity !== undefined) {
+      await StorageModule._writeSecure('ss_identity', data.identity);
+    }
+    if (data.mappings !== undefined) {
+      await StorageModule._writeSecure('ss_mappings', data.mappings);
+    }
+    if (data.settings !== undefined) {
+      await StorageModule._writeSecure('ss_settings', data.settings);
+    }
+
+    // Metadata stays plaintext
+    await api.storage.local.set({
       ss_lastModified: data.lastModified,
       ss_sync_notification: { source, time: Date.now() },
-    };
-    if (data.identity !== undefined) toSet.ss_identity = data.identity;
-    if (data.mappings !== undefined) toSet.ss_mappings = data.mappings;
-    if (data.settings !== undefined) toSet.ss_settings = data.settings;
-    await api.storage.local.set(toSet);
+    });
   },
 
   async _getSyncChunkKeys() {

src/options/options.html

@@ -238,7 +238,7 @@
         <div id="syncStatus" style="margin-top:8px;font-size:12px;min-height:16px"></div>
       </div>
 
-      <div style="margin-top:20px;padding-top:16px;border-top:1px solid #e5e7eb">
+      <div id="fileSyncSection" style="margin-top:20px;padding-top:16px;border-top:1px solid #e5e7eb">
         <h3 style="font-size:13px;font-weight:600;margin:0 0 4px">Auto-Sync Folder — fully automatic, no copy-paste</h3>
         <p class="section-desc" style="margin-bottom:8px">
           Pick the same folder in each browser once. Changes are written to

src/options/options.js

@@ -721,6 +721,13 @@ let syncDirHandle = null;
 const SYNC_FILE_NAME = 'silent-send-sync.json';
 
 async function initFileSync() {
+  // Hide the entire section if File System Access API isn't supported
+  if (!window.showDirectoryPicker) {
+    const section = $('#fileSyncSection');
+    if (section) section.style.display = 'none';
+    return;
+  }
+
   syncDirHandle = await SilentSendSync.loadSyncDirHandle();
   updateFileSyncUI();
   if (syncDirHandle) {