feat(proto): add 9 streaming RPCs for TUI live data

New poll-to-stream RPCs (gateway adapters):
- broker_gateway: StreamAccountState, StreamSessionStatus
- risk: StreamCircuitBreakerStatus, StreamRiskMetrics
- data_acquisition: StreamDownloadStatus
- ml: StreamModelStatus
- trading_agent: StreamAgentStatus
- trading: StreamPortfolioSummary, StreamOrderBook

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

proto/broker_gateway.proto

@@ -32,6 +32,12 @@ service BrokerGatewayService {
 
   // Health check
   rpc HealthCheck(HealthCheckRequest) returns (HealthCheckResponse);
+
+  // Server-streaming: polls GetAccountState at gateway level
+  rpc StreamAccountState(StreamAccountStateRequest) returns (stream GetAccountStateResponse);
+
+  // Server-streaming: polls GetSessionStatus at gateway level
+  rpc StreamSessionStatus(StreamSessionStatusRequest) returns (stream GetSessionStatusResponse);
 }
 
 // ============================================================================
@@ -203,6 +209,16 @@ enum ExecutionType {
   EXECUTION_TYPE_REJECTED = 4;          // Order rejected
 }
 
+// Streaming request messages
+
+message StreamAccountStateRequest {
+  uint32 interval_seconds = 1; // 0 = server default (3s)
+}
+
+message StreamSessionStatusRequest {
+  uint32 interval_seconds = 1; // 0 = server default (5s)
+}
+
 enum SessionState {
   SESSION_STATE_DISCONNECTED = 0;
   SESSION_STATE_CONNECTED = 1;

proto/data_acquisition.proto

@@ -21,6 +21,15 @@ service DataAcquisitionService {
   // Service Health and Status
   // Check service health and resource availability
   rpc HealthCheck(HealthCheckRequest) returns (HealthCheckResponse);
+
+  // Server-streaming: polls ListDownloadJobs at gateway level
+  rpc StreamDownloadStatus(StreamDownloadStatusRequest) returns (stream ListDownloadJobsResponse);
+}
+
+// Streaming request messages
+
+message StreamDownloadStatusRequest {
+  uint32 interval_seconds = 1; // 0 = server default (5s)
 }
 
 // --- Core Request/Response Messages ---

proto/ml.proto

@@ -39,6 +39,16 @@ service MLService {
   
   // Stream real-time signal strength indicators across models
   rpc StreamSignalStrength(StreamSignalStrengthRequest) returns (stream SignalStrengthEvent);
+
+  // Server-streaming: polls GetModelStatus at gateway level
+  rpc StreamModelStatus(StreamModelStatusRequest) returns (stream GetModelStatusResponse);
+}
+
+// Streaming request messages
+
+message StreamModelStatusRequest {
+  string model_name = 1;       // empty = all models
+  uint32 interval_seconds = 2; // 0 = server default (5s)
 }
 
 // Prediction Messages

proto/risk.proto

@@ -33,6 +33,24 @@ service RiskService {
   
   // Get status of all circuit breakers and safety mechanisms
   rpc GetCircuitBreakerStatus(GetCircuitBreakerStatusRequest) returns (GetCircuitBreakerStatusResponse);
+
+  // Server-streaming: polls GetCircuitBreakerStatus at gateway level
+  rpc StreamCircuitBreakerStatus(StreamCircuitBreakerStatusRequest) returns (stream GetCircuitBreakerStatusResponse);
+
+  // Server-streaming: polls GetRiskMetrics at gateway level
+  rpc StreamRiskMetrics(StreamRiskMetricsRequest) returns (stream GetRiskMetricsResponse);
+}
+
+// Streaming request messages
+
+message StreamCircuitBreakerStatusRequest {
+  optional string symbol = 1;   // Filter by symbol (all if not specified)
+  uint32 interval_seconds = 2;  // 0 = server default (2s)
+}
+
+message StreamRiskMetricsRequest {
+  optional string portfolio_id = 1; // Portfolio identifier (default if not specified)
+  uint32 interval_seconds = 2;      // 0 = server default (3s)
 }
 
 // VaR (Value at Risk) Messages

proto/trading.proto

@@ -59,6 +59,25 @@ service TradingService {
 
   // Get regime transition history for a symbol
   rpc GetRegimeTransitions(GetRegimeTransitionsRequest) returns (GetRegimeTransitionsResponse);
+
+  // Server-streaming: polls GetPortfolioSummary at gateway level
+  rpc StreamPortfolioSummary(StreamPortfolioSummaryRequest) returns (stream GetPortfolioSummaryResponse);
+
+  // Server-streaming: polls GetOrderBook at gateway level
+  rpc StreamOrderBook(StreamOrderBookRequest) returns (stream GetOrderBookResponse);
+}
+
+// Streaming request messages
+
+message StreamPortfolioSummaryRequest {
+  string account_id = 1;       // Account ID for portfolio summary
+  uint32 interval_seconds = 2; // 0 = server default (3s)
+}
+
+message StreamOrderBookRequest {
+  string symbol = 1;
+  int32 depth = 2;
+  uint32 interval_seconds = 3; // 0 = server default (1s)
 }
 
 // Order Management Messages

proto/trading_agent.proto

@@ -61,6 +61,15 @@ service TradingAgentService {
 
   // Service Health
   rpc HealthCheck(HealthCheckRequest) returns (HealthCheckResponse);
+
+  // Server-streaming: polls GetAgentStatus at gateway level
+  rpc StreamAgentStatus(StreamAgentStatusRequest) returns (stream GetAgentStatusResponse);
+}
+
+// Streaming request messages
+
+message StreamAgentStatusRequest {
+  uint32 interval_seconds = 1; // 0 = server default (3s)
 }
 
 // Universe Selection Messages