feat(metrics): add 6 hyperopt Prometheus metrics to training_metrics

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

crates/common/src/metrics/training_metrics.rs

@@ -1,6 +1,6 @@
 //! Prometheus metrics for ML training binaries.
 //!
-//! Registers the 18 metrics expected by the Training Cockpit Grafana dashboard
+//! Registers the 24 metrics expected by the Training Cockpit Grafana dashboard
 //! and provides typed helper functions so callers never mis-spell metric names.
 //!
 //! # Usage
@@ -26,7 +26,7 @@ use super::{
 // Registration
 // ---------------------------------------------------------------------------
 
-/// Register all 18 training metrics with the global Prometheus registry.
+/// Register all 24 training metrics with the global Prometheus registry.
 ///
 /// Safe to call multiple times — the registry silently ignores duplicates.
 pub fn init() {
@@ -128,6 +128,43 @@ pub fn init() {
         "foxhunt_training_active_workers",
         "Number of active training workers",
     );
+
+    // Hyperopt gauges (model only)
+    _ = register_gauge_vec(
+        "foxhunt_hyperopt_trial_current",
+        "Current trial number (1-indexed)",
+        m,
+    );
+    _ = register_gauge_vec(
+        "foxhunt_hyperopt_trial_total",
+        "Total trials configured",
+        m,
+    );
+    _ = register_gauge_vec(
+        "foxhunt_hyperopt_best_objective",
+        "Best objective value so far (Sharpe)",
+        m,
+    );
+    _ = register_gauge_vec(
+        "foxhunt_hyperopt_mode",
+        "1=hyperopt active, 0=training only",
+        m,
+    );
+
+    // Hyperopt counters (model only)
+    _ = register_counter_vec(
+        "foxhunt_hyperopt_trials_failed_total",
+        "Failed trials count",
+        m,
+    );
+
+    // Hyperopt histogram (model only)
+    _ = register_histogram_vec(
+        "foxhunt_hyperopt_trial_duration_seconds",
+        "Duration of each trial",
+        m,
+        vec![5.0, 15.0, 30.0, 60.0, 120.0, 300.0, 600.0],
+    );
 }
 
 // ---------------------------------------------------------------------------
@@ -233,3 +270,71 @@ pub fn record_data_load(model: &str, duration_secs: f64) {
 pub fn set_active_workers(value: f64) {
     set_gauge("foxhunt_training_active_workers", value);
 }
+
+pub fn set_hyperopt_trial(model: &str, current: f64, total: f64) {
+    set_gauge_vec("foxhunt_hyperopt_trial_current", &[model], current);
+    set_gauge_vec("foxhunt_hyperopt_trial_total", &[model], total);
+}
+
+pub fn set_hyperopt_best_objective(model: &str, value: f64) {
+    set_gauge_vec("foxhunt_hyperopt_best_objective", &[model], value);
+}
+
+pub fn record_hyperopt_trial_duration(model: &str, secs: f64) {
+    observe_histogram_vec("foxhunt_hyperopt_trial_duration_seconds", &[model], secs);
+}
+
+pub fn record_hyperopt_trial_failure(model: &str) {
+    increment_counter_vec("foxhunt_hyperopt_trials_failed_total", &[model], 1.0);
+}
+
+pub fn set_hyperopt_mode(model: &str, active: bool) {
+    set_gauge_vec(
+        "foxhunt_hyperopt_mode",
+        &[model],
+        if active { 1.0 } else { 0.0 },
+    );
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_init_is_idempotent() {
+        init();
+        init(); // calling twice must not panic
+    }
+
+    #[test]
+    fn test_set_hyperopt_trial() {
+        init();
+        set_hyperopt_trial("dqn", 5.0, 20.0);
+        // No panic = success (gauge_vec values not directly readable without label matching)
+    }
+
+    #[test]
+    fn test_set_hyperopt_mode() {
+        init();
+        set_hyperopt_mode("dqn", true);
+        set_hyperopt_mode("dqn", false);
+    }
+
+    #[test]
+    fn test_record_hyperopt_trial_failure() {
+        init();
+        record_hyperopt_trial_failure("ppo");
+    }
+
+    #[test]
+    fn test_set_hyperopt_best_objective() {
+        init();
+        set_hyperopt_best_objective("tft", 2.34);
+    }
+
+    #[test]
+    fn test_record_hyperopt_trial_duration() {
+        init();
+        record_hyperopt_trial_duration("dqn", 45.3);
+    }
+}