refactor(ml): consolidate 13 duplicate OHLCVBar structs into canonical types module

Introduces ml/src/types/ohlcv.rs as the single source of truth for
OHLCVBar (DateTime<Utc>, f64). Replaces 13 identical struct definitions
scattered across features/, regime/, real_data_loader, and evaluation/.

The f32 backtesting variant in evaluation/metrics.rs is renamed to
OHLCVBarF32 to distinguish it from the canonical type. The regime_adx.rs
i64-timestamp variant was safely migrated since its timestamp field was
never accessed. The orchestrator's Bar alias is replaced with OHLCVBar.

39 files changed, -151 net lines removed.

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

services/trading_agent_service/src/service.rs

@@ -49,7 +49,7 @@ impl TradingAgentServiceImpl {
         &self,
         symbol: &str,
         limit: i32,
-    ) -> Result<Vec<ml::regime::orchestrator::Bar>, Status> {
+    ) -> Result<Vec<ml::types::OHLCVBar>, Status> {
         let records = sqlx::query!(
             r#"
             SELECT open, close, high, low, volume, timestamp
@@ -76,7 +76,7 @@ impl TradingAgentServiceImpl {
                 let low = r.low? as f64 / 100.0;
                 let volume = r.volume? as f64;
 
-                Some(ml::regime::orchestrator::Bar {
+                Some(ml::types::OHLCVBar {
                     timestamp: r.timestamp,
                     open,
                     high,