fix(adapters): ensure placeholder cleanup on message_complete

When all buffered text has already been flushed via periodic timer,
buf.complete() calls flush(true) which returns early on empty buffer,
skipping the onFlush callback that cleans up placeholder state.
This causes subsequent messages to keep editing the old completed
message instead of creating a new one.

Add explicit placeholder cleanup in message_complete handler as
a safety net, matching the same pattern used for tool_use finalization.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

adapters/feishu/index.ts

@@ -333,6 +333,16 @@ async function handleServerMessage(chatId: string, msg: ServerMessage): Promise<
 
     case 'message_complete':
       await buf.complete()
+      // Ensure state is always cleaned up even if buffer was already empty
+      if (state.replyMessageId) {
+        const text = accumulatedText.get(chatId)
+        if (text?.trim()) {
+          await patchMessage(state.replyMessageId, text)
+        }
+        accumulatedText.delete(chatId)
+        chatStates.delete(chatId)
+        buffers.get(chatId)?.reset()
+      }
       break
 
     case 'error':

adapters/telegram/index.ts

@@ -236,6 +236,22 @@ async function handleServerMessage(chatId: string, msg: ServerMessage): Promise<
 
     case 'message_complete':
       await buf.complete()
+      // Ensure placeholder is always cleaned up even if buffer was already empty
+      if (placeholders.has(chatId)) {
+        const text = accumulatedText.get(chatId)
+        if (text?.trim()) {
+          try {
+            const chunks = splitMessage(text, TELEGRAM_TEXT_LIMIT)
+            await bot.api.editMessageText(numericChatId, placeholders.get(chatId)!.messageId, chunks[0]!)
+            for (let i = 1; i < chunks.length; i++) {
+              await bot.api.sendMessage(numericChatId, chunks[i]!)
+            }
+          } catch { /* ignore */ }
+        }
+        placeholders.delete(chatId)
+        accumulatedText.delete(chatId)
+        buffers.get(chatId)?.reset()
+      }
       break
 
     case 'error':