fix(stash): avoid nip44 getter entirely — check login type + window.nostr directly

The NUser extension signer's .nip44 getter calls .nostr which throws
"Browser extension not available" when window.nostr is absent. A try/catch
around ?.nip44 doesn't work because esbuild optimises it away.

Fix: check login type + window.nostr directly (no getter, no throw) to
determine nip44 availability, and wrap all actual signer accesses at
call-time in their own try/catch.

Co-authored-by: shakespeare.diy <assistant@shakespeare.diy>

src/hooks/useStash.ts

@@ -1,6 +1,7 @@
 import { useCallback, useMemo } from 'react';
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useNostr } from '@nostrify/react';
+import { useNostrLogin } from '@nostrify/react/login';
 import { useCurrentUser } from './useCurrentUser';
 import { useNostrPublish } from './useNostrPublish';
 
@@ -47,14 +48,26 @@ const STASH_D_TAG = 'skatespots-stash';
 export function useStash() {
   const { nostr } = useNostr();
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const queryClient = useQueryClient();
   const { mutateAsync: createEvent } = useNostrPublish();
 
-  // Safely check if nip44 is available without throwing (some signers throw
-  // "Browser extension not available" when the getter is accessed with no login)
-  const hasNip44 = (() => {
-    try { return !!user?.signer?.nip44; } catch { return false; }
-  })();
+  // Determine if nip44 is safely available WITHOUT touching any throwing getter.
+  // Extension signers throw "Browser extension not available" from their .nostr
+  // getter when window.nostr isn't present yet (page load race, or no extension).
+  // We check the login type instead: nsec and bunker have nip44 built-in always;
+  // extension logins only have it when window.nostr is present; amber never has it.
+  const hasNip44 = useMemo(() => {
+    if (!user?.pubkey) return false;
+    const login = logins.find((l) => l.pubkey === user.pubkey);
+    if (!login) return false;
+    // nsec and bunker: nip44 is always available (pure JS, no external dep)
+    if (login.type === 'nsec' || login.type === 'bunker') return true;
+    // extension: safe to check window.nostr directly (no getter, no throw)
+    if (login.type === 'extension') return !!(globalThis as { nostr?: { nip44?: unknown } }).nostr?.nip44;
+    // amber / unknown: no nip44 support
+    return false;
+  }, [user?.pubkey, logins]);
 
   // Fetch and decrypt stash
   const { data: stash, isLoading, error } = useQuery({
@@ -81,8 +94,12 @@ export function useStash() {
       const event = events[0];
 
       try {
-        // Decrypt the content (encrypted to self)
-        const decrypted = await user.signer!.nip44!.decrypt(user.pubkey, event.content);
+        // Decrypt the content (encrypted to self) — access nip44 inside try/catch
+        // to guard against extension signers throwing when window.nostr is gone
+        let nip44Dec: typeof user.signer.nip44;
+        try { nip44Dec = user.signer?.nip44; } catch { return { items: [], updatedAt: 0 }; }
+        if (!nip44Dec) return { items: [], updatedAt: 0 };
+        const decrypted = await nip44Dec.decrypt(user.pubkey, event.content);
         const stashData = JSON.parse(decrypted) as Stash;
         return stashData;
       } catch (err) {
@@ -100,8 +117,13 @@ export function useStash() {
       throw new Error('Encryption not available');
     }
 
+    // Access nip44 inside a try/catch at call time (signer is guaranteed by hasNip44 above)
+    let nip44Enc: typeof user.signer.nip44;
+    try { nip44Enc = user.signer?.nip44; } catch { throw new Error('Encryption not available'); }
+    if (!nip44Enc) throw new Error('Encryption not available');
+
     // Encrypt to self
-    const encrypted = await user.signer!.nip44!.encrypt(user.pubkey, JSON.stringify(newStash));
+    const encrypted = await nip44Enc.encrypt(user.pubkey, JSON.stringify(newStash));
 
     // Publish as replaceable event
     await createEvent({