feat(platform): reaction.gossip span and toggle metadata (Phase 501)

Track hadMeBefore, added, gossipSent on reaction.toggle; emit
reaction.gossip timing span when fanning out to guild mesh.

Co-authored-by: Cursor <[email protected]>

README.md

@@ -59,6 +59,8 @@ Expose a single `EventEmitter` API the UI drives over IPC (`apps/pearcord/index.
 
 **v0.8.463 (Phase 500):** `message.send` `replyToId`; `message.edit` `deltaLength`; `message.delete` `hadReactions`/`reactionCount`. UI split messaging composer guild-loading compositor. Bundle: `npm run test:phase500-messaging`. See [MESSAGING.md](../../docs/MESSAGING.md).
 
+**v0.8.464 (Phase 501):** `reaction.toggle` `added`/`hadMeBefore`/`gossipSent`; `reaction.gossip` span on mesh fanout. UI `syncReactionPanelsDuringGuildLoading`. Bundle: `npm run test:phase501-reactions`. See [REACTIONS.md](../../docs/REACTIONS.md).
+
 **v0.8.446 (Phase 483):** `guild.search` `includeMesh`/`queryLen`; `pin.list` `pinCount`. UI search compositor split + hints. Bundle: `npm run test:phase483-search`. See [SEARCH.md](../../docs/SEARCH.md).
 
 **v0.8.445 (Phase 482):** `message.send` `hasAttachment`/`hasSticker`; `message.edit` `contentChanged`; `message.delete` `wasOwn`. UI messaging compositor + hints. Bundle: `npm run test:phase482-messaging`. See [MESSAGING.md](../../docs/MESSAGING.md).

index.js

@@ -11954,10 +11954,33 @@ class PearcordPlatform extends EventEmitter {
       const user = this.identity.user
       if (!user) throw new Error('register first')
       if (this.mode === 'guild') await this._assertCanParticipate('reaction')
-      const result = await this.messages.toggleReaction(messageId, emoji, user.id)
-      if (this.mode !== 'dm' && this.guild) this.guild.gossipReaction(result)
-      this.emit('reaction', result)
       const emojiKey = String(emoji || '').slice(0, 16)
+      let hadMeBefore = false
+      try {
+        const priorRows = await this.messages.listReactions()
+        hadMeBefore = priorRows.some(
+          (r) =>
+            r.messageId === messageId && r.emoji === emojiKey && r.userId === user.id
+        )
+      } catch (_) {}
+      const result = await this.messages.toggleReaction(messageId, emoji, user.id)
+      let gossipSent = false
+      if (this.mode !== 'dm' && this.guild) {
+        const gossipSpan = this.log.time('reaction.gossip', {
+          messageId,
+          guildId,
+          channelId,
+          emoji: emojiKey
+        })
+        this.guild.gossipReaction(result)
+        gossipSpan.end({
+          removed: result?.removed === true,
+          guildId,
+          channelId
+        })
+        gossipSent = true
+      }
+      this.emit('reaction', result)
       const reactionRows = await this.messages.listReactions()
       const reactionCount = reactionRows.filter(
         (r) => r.messageId === messageId && r.emoji === emojiKey
@@ -11969,6 +11992,9 @@ class PearcordPlatform extends EventEmitter {
         guildId,
         channelId,
         removed: result?.removed === true,
+        added: result?.removed !== true,
+        hadMeBefore,
+        gossipSent,
         reactionCount
       })
       return result