feat(core): 确保三个基础 Clash 模式始终可用

注入无害的 .invalid 域名路由规则，使 sing-box 的
CalculateClashModeList 始终发现 Rule/Global/Direct 模式，
同时 handler 层兜底补全缺失的模式并注册 CommandClashMode。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: mapleafgo

core/handler.go

@@ -226,11 +226,21 @@ func (h *ClientHandler) WriteGroups(message libbox.OutboundGroupIterator) {
 }
 
 // InitializeClashMode is called once with the available clash modes.
+// Ensure all three base modes are always present regardless of rule config.
 func (h *ClientHandler) InitializeClashMode(modeList libbox.StringIterator, currentMode string) {
 	var modes []string
 	for modeList.HasNext() {
 		modes = append(modes, modeList.Next())
 	}
+	modeSet := make(map[string]bool, len(modes))
+	for _, m := range modes {
+		modeSet[m] = true
+	}
+	for _, m := range []string{"Rule", "Global", "Direct"} {
+		if !modeSet[m] {
+			modes = append(modes, m)
+		}
+	}
 	h.emit(EventModeUpdate, map[string]any{
 		"modes":        modes,
 		"current_mode": currentMode,

core/handler_test.go

@@ -266,7 +266,7 @@ func TestHandler_InitializeClashMode(t *testing.T) {
 		}
 	})
 
-	h.InitializeClashMode(&stringIterator{items: []string{"rule", "global", "direct"}}, "rule")
+	h.InitializeClashMode(&stringIterator{items: []string{"Rule", "Global", "Direct"}}, "Rule")
 
 	var result map[string]any
 	if err := json.Unmarshal([]byte(got), &result); err != nil {
@@ -276,8 +276,8 @@ func TestHandler_InitializeClashMode(t *testing.T) {
 	if len(modes) != 3 {
 		t.Errorf("modes count = %d, want 3", len(modes))
 	}
-	if result["current_mode"] != "rule" {
-		t.Errorf("current_mode = %v, want rule", result["current_mode"])
+	if result["current_mode"] != "Rule" {
+		t.Errorf("current_mode = %v, want Rule", result["current_mode"])
 	}
 }
 

core/service.go

@@ -211,9 +211,56 @@ func (s *Service) startWithContent(content, ruleSetProxy string) error {
 	}
 	slog.Debug("[startWithContent] config translated", "jsonBytes", len(jsonContent))
 
+	jsonContent = ensureClashModes(jsonContent)
 	return s.startWithJSON(jsonContent, &libbox.OverrideOptions{}, false, nil, nil)
 }
 
+// ensureClashModes injects harmless route rules that reference all three base
+// clash modes so that sing-box's CalculateClashModeList always discovers them.
+// The rules use .invalid domains that never match real traffic.
+func ensureClashModes(jsonContent string) string {
+	var top map[string]json.RawMessage
+	if err := json.Unmarshal([]byte(jsonContent), &top); err != nil {
+		return jsonContent
+	}
+	routeRaw, ok := top["route"]
+	if !ok {
+		return jsonContent
+	}
+	var route map[string]json.RawMessage
+	if err := json.Unmarshal(routeRaw, &route); err != nil {
+		return jsonContent
+	}
+
+	type modeRule struct {
+		Domain    []string `json:"domain"`
+		ClashMode string   `json:"clash_mode"`
+		Outbound  string   `json:"outbound"`
+	}
+	indicators := []modeRule{
+		{Domain: []string{"mode-rule.invalid"}, ClashMode: "Rule", Outbound: "direct"},
+		{Domain: []string{"mode-direct.invalid"}, ClashMode: "Direct", Outbound: "direct"},
+		{Domain: []string{"mode-global.invalid"}, ClashMode: "Global", Outbound: "direct"},
+	}
+
+	var rules []json.RawMessage
+	if raw, ok := route["rules"]; ok {
+		_ = json.Unmarshal(raw, &rules)
+	}
+	for _, r := range indicators {
+		b, _ := json.Marshal(r)
+		rules = append(rules, b)
+	}
+
+	rulesJSON, _ := json.Marshal(rules)
+	route["rules"] = json.RawMessage(rulesJSON)
+	routeJSON, _ := json.Marshal(route)
+	top["route"] = json.RawMessage(routeJSON)
+
+	out, _ := json.Marshal(top)
+	return string(out)
+}
+
 func parseOverrideOptions(jsonStr string) (*libbox.OverrideOptions, OverrideConfig, error) {
 	if jsonStr == "" {
 		return &libbox.OverrideOptions{}, OverrideConfig{}, nil
@@ -290,6 +337,7 @@ func (s *Service) startWithJSON(jsonContent string, override *libbox.OverrideOpt
 	opts.AddCommand(libbox.CommandStatus)
 	opts.AddCommand(libbox.CommandGroup)
 	opts.AddCommand(libbox.CommandConnections)
+	opts.AddCommand(libbox.CommandClashMode)
 
 	newClient := libbox.NewCommandClient(s.handler, opts)
 	slog.Debug("[startWithJSON] calling CommandClient.Connect")