feat(whatsapp): handle reaction removals and improve sender detection

- Emit reaction events with isRemoval flag instead of skipping them
- Fall back to chatJid for DM sender when reaction.key is missing
- Add chatType and accountId to reaction logs for observability
- Update tests to reflect new removal handling behavior

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/web/auto-reply/monitor.ts

@@ -215,14 +215,16 @@ export async function monitorWebChannel(
           },
         });
         const senderLabel = reaction.senderE164 ?? reaction.senderJid ?? "someone";
-        const text = `WhatsApp reaction added: ${reaction.emoji} by ${senderLabel} msg ${reaction.messageId}`;
+        const action = reaction.isRemoval ? "removed" : "added";
+        const emojiPart = reaction.isRemoval ? "" : `: ${reaction.emoji}`;
+        const text = `WhatsApp reaction ${action}${emojiPart} by ${senderLabel} msg ${reaction.messageId}`;
         const contextKey = [
           "whatsapp",
           "reaction",
-          "added",
+          action,
           reaction.messageId,
           reaction.senderJid ?? "unknown",
-          reaction.emoji,
+          reaction.emoji || "removed",
           reaction.chatJid,
         ].join(":");
         enqueueSystemEvent(text, { sessionKey: route.sessionKey, contextKey });

src/web/inbound/monitor.ts

@@ -336,23 +336,42 @@ export async function monitorWebInbox(options: {
           if (chatJid.endsWith("@status") || chatJid.endsWith("@broadcast")) continue;
 
           const emoji = entry.reaction?.text ?? "";
-          // Empty emoji = reaction removed; skip removals (matches Signal behavior)
-          if (!emoji) continue;
+          const isRemoval = !emoji;
 
           const group = isJidGroup(chatJid) === true;
-          // In DMs, reactionKey.fromMe means we reacted (remoteJid is the partner, not us)
-          const senderJid = reactionKey?.fromMe
-            ? (selfJid ?? undefined)
-            : (reactionKey?.participant ?? reactionKey?.remoteJid ?? undefined);
+          // Determine who sent the reaction:
+          // - fromMe=true → we reacted (use selfJid)
+          // - Otherwise: use reaction.key metadata, fallback to chatJid for DMs
+          let senderJid: string | undefined;
+          if (reactionKey?.fromMe) {
+            senderJid = selfJid ?? undefined;
+          } else {
+            // Prefer explicit sender info from reaction.key, fall back to chatJid for DMs
+            senderJid =
+              reactionKey?.participant ?? reactionKey?.remoteJid ?? (group ? undefined : chatJid);
+          }
           const senderE164 = senderJid ? await resolveInboundJid(senderJid) : null;
 
-          inboundLogger.info({ emoji, messageId, chatJid, senderJid }, "inbound reaction");
+          const chatType = group ? "group" : "direct";
+          inboundLogger.info(
+            {
+              emoji: emoji || "(removed)",
+              messageId,
+              chatJid,
+              chatType,
+              senderJid,
+              isRemoval,
+              accountId: options.accountId,
+            },
+            isRemoval ? "inbound reaction removed" : "inbound reaction added",
+          );
 
           options.onReaction({
             messageId,
             emoji,
+            isRemoval,
             chatJid,
-            chatType: group ? "group" : "direct",
+            chatType,
             accountId: options.accountId,
             senderJid: senderJid ?? undefined,
             senderE164: senderE164 ?? undefined,

src/web/inbound/types.ts

@@ -44,8 +44,10 @@ export type WebInboundMessage = {
 export type WebInboundReaction = {
   /** Message ID being reacted to. */
   messageId: string;
-  /** Emoji text (empty string = reaction removed). */
+  /** Emoji text (empty string when isRemoval=true). */
   emoji: string;
+  /** True if this is a reaction removal (emoji will be empty). */
+  isRemoval?: boolean;
   /** JID of the chat where the reaction occurred. */
   chatJid: string;
   chatType: "direct" | "group";

src/web/monitor-inbox.inbound-reactions.test.ts

@@ -142,7 +142,7 @@ describe("web monitor inbox – inbound reactions", () => {
     await listener.close();
   });
 
-  it("skips reaction removals (empty emoji)", async () => {
+  it("handles reaction removals (empty emoji)", async () => {
     const onReaction = vi.fn();
 
     const listener = await monitorWebInbox({
@@ -169,7 +169,14 @@ describe("web monitor inbox – inbound reactions", () => {
     ]);
     await new Promise((resolve) => setImmediate(resolve));
 
-    expect(onReaction).not.toHaveBeenCalled();
+    expect(onReaction).toHaveBeenCalledWith(
+      expect.objectContaining({
+        messageId: "msg-123",
+        emoji: "",
+        isRemoval: true,
+        chatJid: "999@s.whatsapp.net",
+      }),
+    );
 
     await listener.close();
   });
@@ -416,12 +423,13 @@ describe("web monitor inbox – inbound reactions", () => {
     ]);
     await new Promise((resolve) => setImmediate(resolve));
 
+    // In DMs without reaction.key, we use chatJid as the sender
     expect(onReaction).toHaveBeenCalledWith(
       expect.objectContaining({
         messageId: "msg-123",
         emoji: "🔥",
-        senderJid: undefined,
-        senderE164: undefined,
+        senderJid: "999@s.whatsapp.net",
+        chatType: "direct",
       }),
     );