fix: remove redundant SplitMessage in Send() per review feedback

WithMaxMessageLength(4000) already ensures msg.Content ≤ 4000 chars
before reaching Send(), making the SplitMessage call redundant.
The HTML expansion safety net (re-split when >4096 after conversion)
is still preserved.

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

pkg/channels/telegram/telegram.go

@@ -237,14 +237,10 @@ func (c *TelegramChannel) Send(ctx context.Context, msg bus.OutboundMessage) err
 		return nil
 	}
 
-	// Split the raw markdown before converting to HTML so that
-	// SplitMessage's code-fence-aware logic works correctly and
-	// we never break HTML tags/entities by splitting converted output.
-	mdChunks := channels.SplitMessage(msg.Content, 4000)
-
-	// Use a queue so that chunks whose HTML expansion still exceeds
-	// Telegram's 4096-char limit can be re-split until every chunk fits.
-	queue := append([]string{}, mdChunks...)
+	// The Manager already splits messages to ≤4000 chars (WithMaxMessageLength),
+	// so msg.Content is guaranteed to be within that limit. We still need to
+	// check if HTML expansion pushes it beyond Telegram's 4096-char API limit.
+	queue := []string{msg.Content}
 	for len(queue) > 0 {
 		chunk := queue[0]
 		queue = queue[1:]

pkg/channels/telegram/telegram_test.go

@@ -115,7 +115,11 @@ func TestSend_ShortMessage_SingleCall(t *testing.T) {
 	assert.Len(t, caller.calls, 1, "short message should result in exactly one SendMessage call")
 }
 
-func TestSend_LongMessage_MultipleCalls(t *testing.T) {
+func TestSend_LongMessage_SingleCall(t *testing.T) {
+	// With WithMaxMessageLength(4000), the Manager pre-splits messages before
+	// they reach Send(). A message at exactly 4000 chars should go through
+	// as a single SendMessage call (no re-split needed since HTML expansion
+	// won't exceed 4096 for plain text).
 	caller := &stubCaller{
 		callFn: func(ctx context.Context, url string, data *ta.RequestData) (*ta.Response, error) {
 			return successResponse(t), nil
@@ -123,8 +127,7 @@ func TestSend_LongMessage_MultipleCalls(t *testing.T) {
 	}
 	ch := newTestChannel(t, caller)
 
-	// Create a message over 4000 chars so it gets split into multiple chunks.
-	longContent := strings.Repeat("a", 4001)
+	longContent := strings.Repeat("a", 4000)
 
 	err := ch.Send(context.Background(), bus.OutboundMessage{
 		ChatID:  "12345",
@@ -132,7 +135,7 @@ func TestSend_LongMessage_MultipleCalls(t *testing.T) {
 	})
 
 	assert.NoError(t, err)
-	assert.Greater(t, len(caller.calls), 1, "long message should be split into multiple SendMessage calls")
+	assert.Len(t, caller.calls, 1, "pre-split message within limit should result in one SendMessage call")
 }
 
 func TestSend_HTMLFallback_PerChunk(t *testing.T) {