Merge branch 'main' into test

# Conflicts:
#	backend/cmd/server/VERSION
#	backend/ent/migrate/schema.go
#	backend/ent/mutation.go
#	backend/ent/runtime/runtime.go
#	backend/ent/usagelog.go
#	backend/ent/usagelog/usagelog.go
#	backend/ent/usagelog/where.go
#	backend/ent/usagelog_create.go
#	backend/ent/usagelog_update.go
#	backend/internal/repository/usage_log_repo.go
#	backend/internal/server/api_contract_test.go
#	backend/internal/server/middleware/cors.go
#	backend/internal/service/gateway_service.go

backend/internal/pkg/claude/constants.go

@@ -10,6 +10,7 @@ const (
 	BetaInterleavedThinking      = "interleaved-thinking-2025-05-14"
 	BetaFineGrainedToolStreaming = "fine-grained-tool-streaming-2025-05-14"
 	BetaTokenCounting            = "token-counting-2024-11-01"
+	BetaContext1M                = "context-1m-2025-08-07"
 )
 
 // DefaultBetaHeader Claude Code 客户端默认的 anthropic-beta header
@@ -77,6 +78,12 @@ var DefaultModels = []Model{
 		DisplayName: "Claude Opus 4.6",
 		CreatedAt:   "2026-02-06T00:00:00Z",
 	},
+	{
+		ID:          "claude-sonnet-4-6",
+		Type:        "model",
+		DisplayName: "Claude Sonnet 4.6",
+		CreatedAt:   "2026-02-18T00:00:00Z",
+	},
 	{
 		ID:          "claude-sonnet-4-5-20250929",
 		Type:        "model",