Add IPC to prevent Signal session corruption from concurrent connections

When the relay is running, `warelay send` and `warelay heartbeat` now
communicate via Unix socket IPC (~/.warelay/relay.sock) to send messages
through the relay's existing WhatsApp connection.

Previously, these commands created new Baileys sockets that wrote to the
same auth state files, corrupting the Signal session ratchet and causing
the relay's subsequent sends to fail silently.

Changes:
- Add src/web/ipc.ts with Unix socket server/client
- Relay starts IPC server after connecting
- send command tries IPC first, falls back to direct
- heartbeat uses sendWithIpcFallback helper
- inbound.ts exposes sendMessage on listener object
- Messages sent via IPC are added to echo detection set

src/web/auto-reply.ts

@@ -9,12 +9,13 @@ import {
   resolveStorePath,
   saveSessionStore,
 } from "../config/sessions.js";
-import { danger, isVerbose, logVerbose, success } from "../globals.js";
+import { danger, info, isVerbose, logVerbose, success } from "../globals.js";
 import { logInfo } from "../logger.js";
 import { getChildLogger } from "../logging.js";
 import { defaultRuntime, type RuntimeEnv } from "../runtime.js";
 import { normalizeE164 } from "../utils.js";
 import { monitorWebInbox } from "./inbound.js";
+import { sendViaIpc, startIpcServer, stopIpcServer } from "./ipc.js";
 import { loadWebMedia } from "./media.js";
 import { sendMessageWeb } from "./outbound.js";
 import { getQueueSize } from "../process/command-queue.js";
@@ -28,6 +29,26 @@ import {
 } from "./reconnect.js";
 import { getWebAuthAgeMs } from "./session.js";
 
+/**
+ * Send a message via IPC if relay is running, otherwise fall back to direct.
+ * This avoids Signal session corruption from multiple Baileys connections.
+ */
+async function sendWithIpcFallback(
+  to: string,
+  message: string,
+  opts: { verbose: boolean; mediaUrl?: string },
+): Promise<{ messageId: string; toJid: string }> {
+  const ipcResult = await sendViaIpc(to, message, opts.mediaUrl);
+  if (ipcResult?.success && ipcResult.messageId) {
+    if (opts.verbose) {
+      console.log(info(`Sent via relay IPC (avoiding session corruption)`));
+    }
+    return { messageId: ipcResult.messageId, toJid: `${to}@s.whatsapp.net` };
+  }
+  // Fall back to direct send
+  return sendMessageWeb(to, message, opts);
+}
+
 const DEFAULT_WEB_MEDIA_BYTES = 5 * 1024 * 1024;
 type WebInboundMsg = Parameters<
   typeof monitorWebInbox
@@ -95,7 +116,7 @@ export async function runWebHeartbeatOnce(opts: {
   } = opts;
   const _runtime = opts.runtime ?? defaultRuntime;
   const replyResolver = opts.replyResolver ?? getReplyFromConfig;
-  const sender = opts.sender ?? sendMessageWeb;
+  const sender = opts.sender ?? sendWithIpcFallback;
   const runId = newConnectionId();
   const heartbeatLogger = getChildLogger({
     module: "web-heartbeat",
@@ -526,6 +547,8 @@ export async function monitorWebProvider(
     const listener = await (listenerFactory ?? monitorWebInbox)({
       verbose,
       onMessage: async (msg) => {
+        // Also add IPC-sent messages to echo detection
+        // (this is handled below in the IPC sendHandler)
         handledMessages += 1;
         lastMessageAt = Date.now();
         const ts = msg.timestamp
@@ -677,7 +700,33 @@ export async function monitorWebProvider(
       },
     });
 
+    // Start IPC server so `warelay send` can use this connection
+    // instead of creating a new one (which would corrupt Signal session)
+    if ("sendMessage" in listener) {
+      startIpcServer(async (to, message, mediaUrl) => {
+        let mediaBuffer: Buffer | undefined;
+        let mediaType: string | undefined;
+        if (mediaUrl) {
+          const media = await loadWebMedia(mediaUrl);
+          mediaBuffer = media.buffer;
+          mediaType = media.contentType;
+        }
+        const result = await listener.sendMessage(to, message, mediaBuffer, mediaType);
+        // Add to echo detection so we don't process our own message
+        if (message) {
+          recentlySent.add(message);
+          if (recentlySent.size > MAX_RECENT_MESSAGES) {
+            const firstKey = recentlySent.values().next().value;
+            if (firstKey) recentlySent.delete(firstKey);
+          }
+        }
+        logInfo(`📤 IPC send to ${to}: ${message.substring(0, 50)}...`, runtime);
+        return result;
+      });
+    }
+
     const closeListener = async () => {
+      stopIpcServer();
       if (heartbeat) clearInterval(heartbeat);
       if (replyHeartbeatTimer) clearInterval(replyHeartbeatTimer);
       if (watchdogTimer) clearInterval(watchdogTimer);