feat(messages): cross-channel jump-to-reply resolution

Add resolveMessageJump and jumpToMessage so the UI can navigate to
reply parents in other text/DM channels before scrolling and highlighting.

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

index.js

@@ -2095,6 +2095,49 @@ class PearcordPlatform extends EventEmitter {
     }
   }
 
+  /** Locate a message by id across DM or guild text-like channels. */
+  async resolveMessageJump (messageId) {
+    const mid = String(messageId || '')
+    if (!mid) return null
+    if (this.mode === 'dm') {
+      const dms = await this.listDMConversations()
+      for (const ch of dms) {
+        const row = await this.db.get(COLLECTIONS.MESSAGES, { channelId: ch.id, id: mid })
+        if (row) {
+          return { message: enrichMessageRow(row), channelId: ch.id }
+        }
+      }
+      return null
+    }
+    if (!this.guild?.guild) return null
+    const channels = await this.guild.listChannels()
+    for (const ch of channels) {
+      if (
+        ch.type !== 'text' &&
+        ch.type !== 'thread' &&
+        ch.type !== 'forum' &&
+        ch.type !== 'announcement'
+      ) {
+        continue
+      }
+      const row = await this.db.get(COLLECTIONS.MESSAGES, { channelId: ch.id, id: mid })
+      if (row) {
+        return { message: enrichMessageRow(row), channelId: ch.id, channel: ch }
+      }
+    }
+    return null
+  }
+
+  /** Switch channel if needed so the target message is in loaded history. */
+  async jumpToMessage (messageId) {
+    const hit = await this.resolveMessageJump(messageId)
+    if (!hit) return { found: false, messageId: String(messageId || '') }
+    if (hit.channelId !== this.activeChannelId) {
+      await this.selectChannel(hit.channelId)
+    }
+    return { found: true, messageId: hit.message.id, channelId: hit.channelId }
+  }
+
   async joinVoiceChannel (channelId) {
     const guild = this.guild?.guild
     if (!guild || !this.voice) throw new Error('voice not available')