fix: idempotent conv-key upsert + guard tauri-only notification calls

apps/desktop/src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "ChatApp",
-  "version": "0.4.0",
+  "version": "0.4.2",
   "identifier": "com.meinname.chatapp",
   "build": {
     "beforeDevCommand": "pnpm vite:dev",

apps/desktop/src/lib/osNotify.ts

@@ -4,6 +4,8 @@ import {
   sendNotification,
 } from '@tauri-apps/plugin-notification';
 
+import { isTauriRuntime } from './globalShortcut';
+
 // Tracks whether permission has already been requested this session so we
 // don't spam the OS prompt. Actual permission state lives in the OS.
 let permissionChecked = false;
@@ -12,6 +14,11 @@ let permissionGranted = false;
 export async function ensureNotificationPermission(): Promise<boolean> {
   if (permissionChecked) return permissionGranted;
   permissionChecked = true;
+  if (!isTauriRuntime()) {
+    // Web preview / Chrome — Tauri notification plugin not available.
+    permissionGranted = false;
+    return false;
+  }
   try {
     let granted = await isPermissionGranted();
     if (!granted) {
@@ -20,7 +27,6 @@ export async function ensureNotificationPermission(): Promise<boolean> {
     }
     permissionGranted = granted;
   } catch (err: unknown) {
-    // Not running under Tauri (e.g. web preview) — fall back silently.
     permissionGranted = false;
     console.warn('notification permission check failed', err);
   }
@@ -40,6 +46,7 @@ interface NotifyOpts {
 
 export async function notify({ title, body, force = false }: NotifyOpts): Promise<void> {
   if (!force && isAppFocused()) return;
+  if (!isTauriRuntime()) return;
   const granted = await ensureNotificationPermission();
   if (!granted) return;
   try {

apps/desktop/src/lib/secureFileStore.ts

@@ -22,7 +22,17 @@ import sodium from 'libsodium-wrappers';
 // renamed onto `<file>` so an interrupted write never corrupts the existing
 // vault.
 
-const FILE_NAME = 'chatapp-vault.bin';
+// Per-user vault filename so multiple accounts on the same machine each get
+// their own file (and Argon2 derives a different key per user, so cross-user
+// decrypt is also blocked even if filenames collided).
+async function vaultFileName(userId: string): Promise<string> {
+  const enc = new TextEncoder();
+  const buf = await crypto.subtle.digest('SHA-256', enc.encode('chatapp-vault-name:' + userId));
+  const hex = Array.from(new Uint8Array(buf))
+    .map((b) => b.toString(16).padStart(2, '0'))
+    .join('');
+  return 'chatapp-vault-' + hex.slice(0, 16) + '.bin';
+}
 const MAGIC = new TextEncoder().encode('CHATVLT1'); // 8 bytes
 const SALT_LEN = 16;
 const NONCE_LEN = 24;
@@ -79,7 +89,8 @@ async function deriveKey(userId: string, salt: Uint8Array, s: typeof sodium): Pr
 async function loadOrCreateVault(userId: string): Promise<VaultState> {
   const s = await ensureSodium();
   const dir = await appLocalDataDir();
-  const path = joinPath(dir, FILE_NAME);
+  const fileName = await vaultFileName(userId);
+  const path = joinPath(dir, fileName);
   const tmpPath = path + '.tmp';
 
   try {

packages/shared/src/chat/convKeys.ts

@@ -161,7 +161,10 @@ export async function bootstrapConvKey(
     });
   }
 
-  const { error } = await rawFrom(client, 'conversation_keys').insert(rows);
+  const { error } = await rawFrom(client, 'conversation_keys').upsert(rows, {
+    onConflict: 'conversation_id,recipient_device_id,key_version',
+    ignoreDuplicates: true,
+  });
   if (error) throw error;
 
   const handle = { conversationId, keyVersion, key: convKey };
@@ -262,15 +265,21 @@ export async function shareConvKeyToDevice(
     recipientPublicKey,
     own.privateKey,
   );
-  const { error } = await rawFrom(client, 'conversation_keys').insert({
+  const { error } = await rawFrom(client, 'conversation_keys').upsert(
+    {
       conversation_id: conversationId,
       recipient_device_id: recipientDeviceId,
       key_version: version,
       sender_device_id: own.deviceId,
       encrypted_key: bytesToPgHex(wrapped.ciphertext),
       nonce: bytesToPgHex(wrapped.nonce),
-  });
+    },
-  if (error && !String(error.message ?? '').includes('duplicate')) throw error;
+    {
+      onConflict: 'conversation_id,recipient_device_id,key_version',
+      ignoreDuplicates: true,
+    },
+  );
+  if (error) throw error;
 }
 
 // Re-exports for convenience.