Add sender_did to chat messages and new chat tables

Introduces a migration to add a sender_did column to the chat_messages table and creates new tables for chat_device_bundles, chat_inbox, and chat_one_time_keys. Updates related API routes and adds a script for sender DID migration. These changes support device-based messaging and improved chat security.

src/app/api/chat/send/route.ts

@@ -128,13 +128,20 @@ export async function POST(request: NextRequest) {
                 const localDomain = process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost';
                 const swarmMessageId = `swarm:${localDomain}:${messageId}`;
                 
+                // Store full envelope data for decryption
+                const envelopeData = {
+                    did: user.did,
+                    handle: user.handle,
+                    ciphertext: ciphertext
+                };
+                
                 const [newMessage] = await db.insert(chatMessages).values({
                     conversationId: conversation.id,
                     senderHandle: user.handle,
                     senderDisplayName: user.displayName,
                     senderAvatarUrl: user.avatarUrl,
                     senderNodeDomain: null, // Local sender
-                    encryptedContent: ciphertext,
+                    encryptedContent: JSON.stringify(envelopeData), // Full envelope
                     senderChatPublicKey: null, // V2 E2E - keys are in the envelope
                     swarmMessageId,
                     deliveredAt: null, // Will update when remote confirms

src/app/api/swarm/chat/inbox/route.ts

@@ -95,6 +95,13 @@ export async function POST(request: NextRequest) {
       }
 
       // Store message reference so it appears in UI
+      // Store full envelope data as JSON so we can decrypt later
+      const envelopeData = {
+        did: body.did,
+        handle: body.handle,
+        ciphertext: body.data.ciphertext
+      };
+      
       const messageId = crypto.randomUUID();
       await db.insert(chatMessages).values({
         conversationId: conversation.id,
@@ -102,7 +109,7 @@ export async function POST(request: NextRequest) {
         senderDisplayName: null, // Unknown until decrypted
         senderAvatarUrl: null,
         senderNodeDomain: body.did?.split(':')[2] || null,
-        encryptedContent: ciphertext,
+        encryptedContent: JSON.stringify(envelopeData), // Full envelope for decryption
         senderChatPublicKey: null,
         swarmMessageId: `swarm:v2:${messageId}`,
         deliveredAt: new Date(),

src/app/api/swarm/chat/messages/route.ts

@@ -115,7 +115,7 @@ export async function GET(request: NextRequest) {
         // - Received messages: need sender's public key
         senderPublicKey: senderPubKey,
         isE2E: !!msg.senderChatPublicKey || (isSentByMe && !!recipientPublicKey),
-        encryptedContent: msg.encryptedContent,
+        encryptedContent: msg.encryptedContent, // This is now the full envelope JSON
         deliveredAt: msg.deliveredAt,
         readAt: msg.readAt,
         createdAt: msg.createdAt,