fix(auth): break credits cold-start deadlock by keeping unknown-hint auths as fallback candidates

Replace antigravityCreditsAvailableForModel with inline known/unknown
split. Auths whose credit hints are not yet populated are kept as
lower-priority candidates instead of being rejected, breaking the
chicken-and-egg deadlock at cold start.

sdk/cliproxy/auth/conductor.go

@@ -2910,7 +2910,8 @@ func (m *Manager) findAllAntigravityCreditsCandidateAuths(routeModel string, opt
 	pinnedAuthID := pinnedAuthIDFromMetadata(opts.Metadata)
 	m.mu.RLock()
 	defer m.mu.RUnlock()
-	var candidates []creditsCandidateEntry
+	var known []creditsCandidateEntry
+	var unknown []creditsCandidateEntry
 	for _, auth := range m.auths {
 		if auth == nil || auth.Disabled || auth.Status == StatusDisabled {
 			continue
@@ -2918,7 +2919,10 @@ func (m *Manager) findAllAntigravityCreditsCandidateAuths(routeModel string, opt
 		if pinnedAuthID != "" && auth.ID != pinnedAuthID {
 			continue
 		}
-		if !antigravityCreditsAvailableForModel(auth, routeModel) {
+		if !strings.EqualFold(strings.TrimSpace(auth.Provider), "antigravity") {
+			continue
+		}
+		if !strings.Contains(strings.ToLower(strings.TrimSpace(routeModel)), "claude") {
 			continue
 		}
 		providerKey := strings.TrimSpace(strings.ToLower(auth.Provider))
@@ -2926,16 +2930,32 @@ func (m *Manager) findAllAntigravityCreditsCandidateAuths(routeModel string, opt
 		if !ok {
 			continue
 		}
-		candidates = append(candidates, creditsCandidateEntry{
+
+		hint, okHint := GetAntigravityCreditsHint(auth.ID)
+		if okHint && hint.Known {
+			if !hint.Available {
+				continue
+			}
+			known = append(known, creditsCandidateEntry{
+				auth:     auth.Clone(),
+				executor: executor,
+				provider: providerKey,
+			})
+			continue
+		}
+		unknown = append(unknown, creditsCandidateEntry{
 			auth:     auth.Clone(),
 			executor: executor,
 			provider: providerKey,
 		})
 	}
-	sort.Slice(candidates, func(i, j int) bool {
-		return candidates[i].auth.ID < candidates[j].auth.ID
+	sort.Slice(known, func(i, j int) bool {
+		return known[i].auth.ID < known[j].auth.ID
 	})
-	return candidates
+	sort.Slice(unknown, func(i, j int) bool {
+		return unknown[i].auth.ID < unknown[j].auth.ID
+	})
+	return append(known, unknown...)
 }
 
 type creditsCandidateEntry struct {

sdk/cliproxy/auth/conductor_credits_candidates_test.go

@@ -0,0 +1,61 @@
+package auth
+
+import (
+	"testing"
+	"time"
+
+	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/executor"
+)
+
+func TestFindAllAntigravityCreditsCandidateAuths_PrefersKnownCreditsThenUnknown(t *testing.T) {
+	m := &Manager{
+		auths: map[string]*Auth{
+			"zz-credits": {ID: "zz-credits", Provider: "antigravity"},
+			"aa-unknown": {ID: "aa-unknown", Provider: "antigravity"},
+			"mm-no":      {ID: "mm-no", Provider: "antigravity"},
+		},
+		executors: map[string]ProviderExecutor{
+			"antigravity": schedulerTestExecutor{},
+		},
+	}
+
+	SetAntigravityCreditsHint("zz-credits", AntigravityCreditsHint{
+		Known:     true,
+		Available: true,
+		UpdatedAt: time.Now(),
+	})
+	SetAntigravityCreditsHint("mm-no", AntigravityCreditsHint{
+		Known:     true,
+		Available: false,
+		UpdatedAt: time.Now(),
+	})
+
+	opts := cliproxyexecutor.Options{}
+
+	candidates := m.findAllAntigravityCreditsCandidateAuths("claude-sonnet-4-6", opts)
+	if len(candidates) != 2 {
+		t.Fatalf("candidates len = %d, want 2", len(candidates))
+	}
+	if candidates[0].auth.ID != "zz-credits" {
+		t.Fatalf("candidates[0].auth.ID = %q, want %q", candidates[0].auth.ID, "zz-credits")
+	}
+	if candidates[1].auth.ID != "aa-unknown" {
+		t.Fatalf("candidates[1].auth.ID = %q, want %q", candidates[1].auth.ID, "aa-unknown")
+	}
+
+	nonClaude := m.findAllAntigravityCreditsCandidateAuths("gemini-3-flash", opts)
+	if len(nonClaude) != 0 {
+		t.Fatalf("nonClaude len = %d, want 0", len(nonClaude))
+	}
+
+	pinnedOpts := cliproxyexecutor.Options{
+		Metadata: map[string]any{cliproxyexecutor.PinnedAuthMetadataKey: "aa-unknown"},
+	}
+	pinned := m.findAllAntigravityCreditsCandidateAuths("claude-sonnet-4-6", pinnedOpts)
+	if len(pinned) != 1 {
+		t.Fatalf("pinned len = %d, want 1", len(pinned))
+	}
+	if pinned[0].auth.ID != "aa-unknown" {
+		t.Fatalf("pinned[0].auth.ID = %q, want %q", pinned[0].auth.ID, "aa-unknown")
+	}
+}