fix(line): log loading refresh errors, skip typing without recorder

Address review feedback from @alexhoshina and Codex:
- Log sendLoading errors in ticker goroutine instead of discarding
- Only start typing indicator when PlaceholderRecorder is available
  to avoid wasted API calls and unnecessary goroutine creation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/channels/line/line.go

@@ -380,7 +380,9 @@ func (c *LINEChannel) processEvent(event lineEvent) {
 
 	// Thinking indicator (LINE loading animation is 1:1 only).
 	// For group/room chats, LINE provides no equivalent API.
+	// Only start if PlaceholderRecorder is available to avoid wasted API calls.
 	if !isGroup {
+		if rec := c.GetPlaceholderRecorder(); rec != nil {
 			typingCtx, typingCancel := context.WithTimeout(c.ctx, 5*time.Minute)
 			stop, err := c.StartTyping(typingCtx, chatID)
 			if err == nil {
@@ -391,16 +393,12 @@ func (c *LINEChannel) processEvent(event lineEvent) {
 						typingCancel()
 					})
 				}
-			if rec := c.GetPlaceholderRecorder(); rec != nil {
 				rec.RecordTypingStop("line", chatID, stopFn)
-			} else {
-				// No recorder — stop immediately to avoid goroutine leaks.
-				stopFn()
-			}
 			} else {
 				typingCancel()
 			}
 		}
+	}
 
 	c.HandleMessage(c.ctx, peer, msg.ID, senderID, chatID, content, mediaPaths, metadata, sender)
 }
@@ -627,7 +625,11 @@ func (c *LINEChannel) StartTyping(ctx context.Context, chatID string) (func(), e
 			case <-typingCtx.Done():
 				return
 			case <-ticker.C:
-				_ = c.sendLoading(typingCtx, chatID)
+				if err := c.sendLoading(typingCtx, chatID); err != nil {
+					logger.DebugCF("line", "Failed to refresh loading indicator", map[string]any{
+						"error": err.Error(),
+					})
+				}
 			}
 		}
 	}()