fix(rate-limits): treat empty policies as unlimited

apps/api/internal/httpapi/model_catalog.go

@@ -476,16 +476,17 @@ func discountTitle(label string, discount float64) string {
 }
 
 func effectiveModelRateLimits(model store.PlatformModel, platform store.Platform, runtimePolicyMap map[string]store.RuntimePolicySet) ModelCatalogRateLimits {
-	overridePolicy := objectValue(model.RuntimePolicyOverride["rateLimitPolicy"])
+	overridePolicyRaw, hasOverridePolicy := model.RuntimePolicyOverride["rateLimitPolicy"]
+	overridePolicy := objectValue(overridePolicyRaw)
 	runtimePolicy := map[string]any(nil)
 	if model.RuntimePolicySetID != "" {
 		runtimePolicy = runtimePolicyMap[model.RuntimePolicySetID].RateLimitPolicy
 	}
-	policies := []map[string]any{
-		overridePolicy,
-		model.RateLimitPolicy,
-		runtimePolicy,
-		platform.RateLimitPolicy,
+	policies := []rateLimitPolicySource{
+		{policy: overridePolicy, authoritative: hasOverridePolicy},
+		{policy: model.RateLimitPolicy, authoritative: len(model.RateLimitPolicy) > 0},
+		{policy: runtimePolicy, authoritative: strings.TrimSpace(model.RuntimePolicySetID) != ""},
+		{policy: platform.RateLimitPolicy},
 	}
 	limits := ModelCatalogRateLimits{
 		RPM:        firstRateLimit(policies, "rpm"),
@@ -496,18 +497,26 @@ func effectiveModelRateLimits(model store.PlatformModel, platform store.Platform
 	return limits
 }
 
-func firstRateLimit(policies []map[string]any, metric string) *float64 {
-	for _, policy := range policies {
-		if value := readRateLimit(policy, metric); value != nil {
-			return value
+type rateLimitPolicySource struct {
+	policy        map[string]any
+	authoritative bool
+}
+
+func firstRateLimit(policies []rateLimitPolicySource, metric string) *float64 {
+	for _, source := range policies {
+		if value, ok := readRateLimit(source.policy, metric); ok {
+			return floatPointer(value)
+		}
+		if source.authoritative {
+			return floatPointer(0)
 		}
 	}
 	return nil
 }
 
-func readRateLimit(policy map[string]any, metric string) *float64 {
+func readRateLimit(policy map[string]any, metric string) (float64, bool) {
 	if len(policy) == 0 {
-		return nil
+		return 0, false
 	}
 	if rules, ok := policy["rules"].([]any); ok {
 		for _, item := range rules {
@@ -516,22 +525,22 @@ func readRateLimit(policy map[string]any, metric string) *float64 {
 				continue
 			}
 			if limit, ok := numberValue(rule["limit"]); ok {
-				return &limit
+				return limit, true
 			}
 		}
 	}
 	for _, key := range rateLimitKeys(metric) {
 		if value, ok := numberValue(policy[key]); ok {
-			return &value
+			return value, true
 		}
 	}
 	platformLimits := objectValue(policy["platformLimits"])
 	for _, key := range rateLimitKeys(metric) {
 		if value, ok := numberValue(platformLimits[key]); ok {
-			return &value
+			return value, true
 		}
 	}
-	return nil
+	return 0, false
 }
 
 func rateLimitKeys(metric string) []string {
@@ -1367,12 +1376,16 @@ func numberValue(value any) (float64, bool) {
 }
 
 func formatOptionalNumber(value *float64) string {
-	if value == nil {
-		return "-"
+	if value == nil || *value <= 0 {
+		return "不限"
 	}
 	return formatLimitNumber(*value)
 }
 
+func floatPointer(value float64) *float64 {
+	return &value
+}
+
 func formatLimitNumber(value float64) string {
 	switch {
 	case absFloat(value) >= 10000: