fix(ml): silence unsafe-code warnings on inference adapter Send/Sync impls

Add #[allow(unsafe_code)] on each unsafe impl Send/Sync for the four
inference adapters (DQN, PPO, TFT, Mamba2). The SAFETY comments explain
why these are sound — Mutex provides exclusive access.

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

ml/src/ensemble/adapters/dqn.rs

@@ -26,7 +26,9 @@ pub struct DqnInferenceAdapter {
 
 // SAFETY: DQN internally uses candle tensors which are Send+Sync.
 // The Mutex provides exclusive access for inference calls.
+#[allow(unsafe_code)]
 unsafe impl Send for DqnInferenceAdapter {}
+#[allow(unsafe_code)]
 unsafe impl Sync for DqnInferenceAdapter {}
 
 impl DqnInferenceAdapter {

ml/src/ensemble/adapters/mamba2.rs

@@ -37,7 +37,9 @@ pub struct Mamba2InferenceAdapter {
 
 // SAFETY: Mamba2SSM internally uses candle tensors which are Send+Sync.
 // The Mutex provides exclusive access for inference calls and buffer mutation.
+#[allow(unsafe_code)]
 unsafe impl Send for Mamba2InferenceAdapter {}
+#[allow(unsafe_code)]
 unsafe impl Sync for Mamba2InferenceAdapter {}
 
 impl Mamba2InferenceAdapter {

ml/src/ensemble/adapters/ppo.rs

@@ -28,7 +28,9 @@ pub struct PpoInferenceAdapter {
 
 // SAFETY: PPO internally uses candle tensors which are Send+Sync.
 // The Mutex provides exclusive access for inference calls.
+#[allow(unsafe_code)]
 unsafe impl Send for PpoInferenceAdapter {}
+#[allow(unsafe_code)]
 unsafe impl Sync for PpoInferenceAdapter {}
 
 impl PpoInferenceAdapter {

ml/src/ensemble/adapters/tft.rs

@@ -40,7 +40,9 @@ pub struct TftInferenceAdapter {
 
 // SAFETY: TemporalFusionTransformer internally uses candle tensors which
 // are Send+Sync.  The Mutex provides exclusive access for inference calls.
+#[allow(unsafe_code)]
 unsafe impl Send for TftInferenceAdapter {}
+#[allow(unsafe_code)]
 unsafe impl Sync for TftInferenceAdapter {}
 
 impl TftInferenceAdapter {