test(agent): remove obsolete TestHandleExtensionCommand_EmojiPassthrough

handleExtensionCommand was removed in the : → / prefix refactor.
The tested behavior (:help, :usage) is now handled by the command registry.

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

pkg/agent/loop_test.go

@@ -871,39 +871,6 @@ func TestHandleCdCommand_SymlinkEscape(t *testing.T) {
 	}
 }
 
-// TestHandleExtensionCommand_EmojiPassthrough verifies that emoji-like
-// messages starting with : are not intercepted as commands.
-func TestHandleExtensionCommand_EmojiPassthrough(t *testing.T) {
-	cfg := &config.Config{
-		Agents: config.AgentsConfig{
-			Defaults: config.AgentDefaults{
-				Workspace: t.TempDir(),
-				Model:     "test-model",
-				MaxTokens: 4096,
-			},
-		},
-	}
-	msgBus := bus.NewMessageBus()
-	provider := &mockProvider{}
-	al := NewAgentLoop(cfg, msgBus, provider)
-
-	emojiInputs := []string{":)", ":D", ":heart:", ":thinking:", ":-)", ":100:"}
-	for _, input := range emojiInputs {
-		_, handled := al.handleExtensionCommand(input)
-		if handled {
-			t.Errorf("Expected %q to pass through (not handled), but it was handled", input)
-		}
-	}
-
-	// Known commands should still be handled
-	knownCommands := []string{":help", ":usage"}
-	for _, cmd := range knownCommands {
-		_, handled := al.handleExtensionCommand(cmd)
-		if !handled {
-			t.Errorf("Expected %q to be handled, but it was not", cmd)
-		}
-	}
-}
 
 func TestTargetReasoningChannelID_AllChannels(t *testing.T) {
 	tmpDir, err := os.MkdirTemp("", "agent-test-*")