feat(proto): add epoch financial metrics + GetEpochHistory to monitoring.proto

Add 11 financial fields (sharpe, sortino, win_rate, max_drawdown,
profit_factor, total_return, avg_return, total_trades, action
distribution) to TrainingSession (fields 36-46), a new
GetEpochHistory RPC with request/response messages, and wire the
Prometheus metric mapping in the monitoring service with a
stub RPC handler for task 7.

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

bin/fxt/proto/monitoring.proto

@@ -9,6 +9,10 @@ service MonitoringService {
   // Server-streaming: pushes updates every N seconds
   rpc StreamTrainingMetrics(StreamTrainingMetricsRequest)
       returns (stream GetLiveTrainingMetricsResponse);
+
+  // Epoch history for a specific session (ring buffer, max 50 epochs)
+  rpc GetEpochHistory(GetEpochHistoryRequest)
+      returns (GetEpochHistoryResponse);
 }
 
 message GetLiveTrainingMetricsRequest {
@@ -81,6 +85,20 @@ message TrainingSession {
   uint32 hyperopt_trial_epoch = 33;
   float hyperopt_trial_best_loss = 34;
   float hyperopt_elapsed_seconds = 35;
+
+  // Epoch-level financial metrics
+  float epoch_sharpe = 36;
+  float epoch_sortino = 37;
+  float epoch_win_rate = 38;
+  float epoch_max_drawdown = 39;
+  float epoch_profit_factor = 40;
+  float epoch_total_return = 41;
+  float epoch_avg_return = 42;
+  uint32 epoch_total_trades = 43;
+  // Action distribution
+  float action_buy_pct = 44;
+  float action_sell_pct = 45;
+  float action_hold_pct = 46;
 }
 
 message GpuSnapshot {
@@ -90,3 +108,33 @@ message GpuSnapshot {
   float temperature_celsius = 4;
   float power_watts = 5;
 }
+
+message GetEpochHistoryRequest {
+  string model = 1;
+  string fold = 2;
+  uint32 max_epochs = 3;  // 0 = all (up to 50)
+}
+
+message EpochFinancialSnapshot {
+  uint32 epoch = 1;
+  float sharpe = 2;
+  float sortino = 3;
+  float win_rate = 4;
+  float max_drawdown = 5;
+  float profit_factor = 6;
+  float total_return = 7;
+  float avg_return = 8;
+  uint32 total_trades = 9;
+  float loss = 10;
+  float val_loss = 11;
+  float learning_rate = 12;
+  float action_buy_pct = 13;
+  float action_sell_pct = 14;
+  float action_hold_pct = 15;
+}
+
+message GetEpochHistoryResponse {
+  string model = 1;
+  string fold = 2;
+  repeated EpochFinancialSnapshot epochs = 3;
+}

services/monitoring_service/proto/monitoring.proto

@@ -9,6 +9,10 @@ service MonitoringService {
   // Server-streaming: pushes updates every N seconds
   rpc StreamTrainingMetrics(StreamTrainingMetricsRequest)
       returns (stream GetLiveTrainingMetricsResponse);
+
+  // Epoch history for a specific session (ring buffer, max 50 epochs)
+  rpc GetEpochHistory(GetEpochHistoryRequest)
+      returns (GetEpochHistoryResponse);
 }
 
 message GetLiveTrainingMetricsRequest {
@@ -81,6 +85,20 @@ message TrainingSession {
   uint32 hyperopt_trial_epoch = 33;
   float hyperopt_trial_best_loss = 34;
   float hyperopt_elapsed_seconds = 35;
+
+  // Epoch-level financial metrics
+  float epoch_sharpe = 36;
+  float epoch_sortino = 37;
+  float epoch_win_rate = 38;
+  float epoch_max_drawdown = 39;
+  float epoch_profit_factor = 40;
+  float epoch_total_return = 41;
+  float epoch_avg_return = 42;
+  uint32 epoch_total_trades = 43;
+  // Action distribution
+  float action_buy_pct = 44;
+  float action_sell_pct = 45;
+  float action_hold_pct = 46;
 }
 
 message GpuSnapshot {
@@ -90,3 +108,33 @@ message GpuSnapshot {
   float temperature_celsius = 4;
   float power_watts = 5;
 }
+
+message GetEpochHistoryRequest {
+  string model = 1;
+  string fold = 2;
+  uint32 max_epochs = 3;  // 0 = all (up to 50)
+}
+
+message EpochFinancialSnapshot {
+  uint32 epoch = 1;
+  float sharpe = 2;
+  float sortino = 3;
+  float win_rate = 4;
+  float max_drawdown = 5;
+  float profit_factor = 6;
+  float total_return = 7;
+  float avg_return = 8;
+  uint32 total_trades = 9;
+  float loss = 10;
+  float val_loss = 11;
+  float learning_rate = 12;
+  float action_buy_pct = 13;
+  float action_sell_pct = 14;
+  float action_hold_pct = 15;
+}
+
+message GetEpochHistoryResponse {
+  string model = 1;
+  string fold = 2;
+  repeated EpochFinancialSnapshot epochs = 3;
+}

services/monitoring_service/src/service.rs

@@ -8,8 +8,9 @@ use tonic::{Request, Response, Status};
 use tracing::error;
 
 use crate::monitoring::{
-    monitoring_service_server::MonitoringService, GetLiveTrainingMetricsRequest,
-    GetLiveTrainingMetricsResponse, GpuSnapshot, StreamTrainingMetricsRequest, TrainingSession,
+    monitoring_service_server::MonitoringService, GetEpochHistoryRequest,
+    GetEpochHistoryResponse, GetLiveTrainingMetricsRequest, GetLiveTrainingMetricsResponse,
+    GpuSnapshot, StreamTrainingMetricsRequest, TrainingSession,
 };
 use crate::prometheus_client::{MetricSample, PrometheusClient};
 
@@ -92,6 +93,16 @@ impl MonitoringService for MonitoringServiceImpl {
 
         Ok(Response::new(Box::pin(stream)))
     }
+
+    async fn get_epoch_history(
+        &self,
+        _request: Request<GetEpochHistoryRequest>,
+    ) -> Result<Response<GetEpochHistoryResponse>, Status> {
+        // TODO(task-7): wire to epoch ring buffer storage
+        Err(Status::unimplemented(
+            "GetEpochHistory not yet wired — see task 7",
+        ))
+    }
 }
 
 /// Group flat metric samples into TrainingSession structs keyed by (model, fold)
@@ -178,6 +189,29 @@ fn group_into_sessions(samples: &[MetricSample], model_filter: &str) -> Vec<Trai
             "foxhunt_hyperopt_elapsed_seconds" => {
                 session.hyperopt_elapsed_seconds = s.value as f32;
             }
+            // Epoch-level financial metrics
+            "foxhunt_training_epoch_sharpe" => session.epoch_sharpe = s.value as f32,
+            "foxhunt_training_epoch_sortino" => session.epoch_sortino = s.value as f32,
+            "foxhunt_training_epoch_win_rate" => session.epoch_win_rate = s.value as f32,
+            "foxhunt_training_epoch_max_drawdown" => {
+                session.epoch_max_drawdown = s.value as f32;
+            }
+            "foxhunt_training_epoch_profit_factor" => {
+                session.epoch_profit_factor = s.value as f32;
+            }
+            "foxhunt_training_epoch_total_return" => {
+                session.epoch_total_return = s.value as f32;
+            }
+            "foxhunt_training_epoch_avg_return" => {
+                session.epoch_avg_return = s.value as f32;
+            }
+            "foxhunt_training_epoch_total_trades" => {
+                session.epoch_total_trades = s.value as u32;
+            }
+            // Action distribution
+            "foxhunt_training_action_buy_pct" => session.action_buy_pct = s.value as f32,
+            "foxhunt_training_action_sell_pct" => session.action_sell_pct = s.value as f32,
+            "foxhunt_training_action_hold_pct" => session.action_hold_pct = s.value as f32,
             _ => {}
         }
     }