fix: support ExtensionSigner NIP-44 API pattern

Problem:
Browser extension signers (nos2x, Alby, etc.) were failing with:
"Signer does not support NIP-44 decryption"

Root Cause:
ExtensionSigner exposes NIP-44 as signer.nip44.encrypt/decrypt
Other signers expose it as signer.nip44Encrypt/nip44Decrypt

Solution:
Created helper functions that try both patterns:
1. Direct methods (PasswordSigner, NostrConnectSigner)
2. nip44 getter methods (ExtensionSigner)

Files Changed:
- src/services/gift-wrap.ts: nip44Decrypt helper in decryptGiftWrap
- src/lib/chat/adapters/nip-17-adapter.ts: nip44Encrypt helper in sendMessage

This enables NIP-17 DMs to work with all signer types.

src/lib/chat/adapters/nip-17-adapter.ts

@@ -168,10 +168,26 @@ export class Nip17Adapter extends ChatProtocolAdapter {
       throw new Error("No active account or signer");
     }
 
-    // Check if signer supports NIP-44 encryption
-    if (!activeSigner.nip44Encrypt) {
+    // Helper to call NIP-44 encrypt (supports both signer patterns)
+    const nip44Encrypt = async (
+      pubkey: string,
+      plaintext: string,
+    ): Promise<string> => {
+      // Try direct method (PasswordSigner, NostrConnectSigner, etc.)
+      if (typeof activeSigner.nip44Encrypt === "function") {
+        return await activeSigner.nip44Encrypt(pubkey, plaintext);
+      }
+
+      // Try nip44 getter (ExtensionSigner)
+      if (
+        activeSigner.nip44 &&
+        typeof activeSigner.nip44.encrypt === "function"
+      ) {
+        return await activeSigner.nip44.encrypt(pubkey, plaintext);
+      }
+
       throw new Error("Signer does not support NIP-44 encryption");
-    }
+    };
 
     const recipientPubkey = conversation.participants.find(
       (p) => p.pubkey !== activePubkey,
@@ -230,10 +246,7 @@ export class Nip17Adapter extends ChatProtocolAdapter {
     // Step 2: Create the seal (kind 13)
     // Encrypt the rumor with conversation key (sender → recipient)
     const rumorJSON = JSON.stringify(rumor);
-    const encryptedRumor = await activeSigner.nip44Encrypt(
-      recipientPubkey,
-      rumorJSON,
-    );
+    const encryptedRumor = await nip44Encrypt(recipientPubkey, rumorJSON);
 
     // Sign the seal
     const sealDraft = {

src/services/gift-wrap.ts

@@ -568,17 +568,30 @@ class GiftWrapManager {
       throw new Error("Gift wrap not addressed to this pubkey");
     }
 
+    // Helper to call NIP-44 decrypt (supports both signer patterns)
+    const nip44Decrypt = async (
+      pubkey: string,
+      ciphertext: string,
+    ): Promise<string> => {
+      // Try direct method (PasswordSigner, NostrConnectSigner, etc.)
+      if (typeof signer.nip44Decrypt === "function") {
+        return await signer.nip44Decrypt(pubkey, ciphertext);
+      }
+
+      // Try nip44 getter (ExtensionSigner)
+      if (signer.nip44 && typeof signer.nip44.decrypt === "function") {
+        return await signer.nip44.decrypt(pubkey, ciphertext);
+      }
+
+      throw new Error("Signer does not support NIP-44 decryption");
+    };
+
     // Step 1: Decrypt the gift wrap to get the seal (kind 13)
     // The gift wrap is encrypted with the conversation key between
     // the random ephemeral key (giftWrap.pubkey) and our key (recipientPubkey)
     let sealJSON: string;
     try {
-      // Check if signer has nip44Decrypt capability
-      if (!signer.nip44Decrypt) {
-        throw new Error("Signer does not support NIP-44 decryption");
-      }
-
-      sealJSON = await signer.nip44Decrypt(giftWrap.pubkey, giftWrap.content);
+      sealJSON = await nip44Decrypt(giftWrap.pubkey, giftWrap.content);
     } catch (error) {
       throw new Error(`Failed to decrypt gift wrap: ${error}`);
     }
@@ -601,11 +614,7 @@ class GiftWrapManager {
     // the sender (seal.pubkey) and us (recipientPubkey)
     let rumorJSON: string;
     try {
-      if (!signer.nip44Decrypt) {
-        throw new Error("Signer does not support NIP-44 decryption");
-      }
-
-      rumorJSON = await signer.nip44Decrypt(seal.pubkey, seal.content);
+      rumorJSON = await nip44Decrypt(seal.pubkey, seal.content);
     } catch (error) {
       throw new Error(`Failed to decrypt seal: ${error}`);
     }