fix: resolve audited dispatch, kernel, and rollout bugs

- re-register the linear family with the operator dispatcher (ASTR_OPS / op_backend / resolve)
- fix bf16 gemv misaligned-address faults and element mispairing for offset weights
- reject misaligned bf16_swiglu inputs with a clear error and fall back in the backend gate
- make the rollout reuse decision, validation, and return atomic under one policy snapshot
- add the documented post-scoring rollout version check
- derive live+1 under the scheduler lock in optimizer_step via apply_weight_update(None, ...)
- reject rollout_max_policy_lag below rollout_interval - 1 at config time
- sync gemv stream-test inputs before switching streams; drop dead loader imports

astrai/trainer/strategy.py

@@ -292,8 +292,9 @@ class BaseStrategy(ABC):
         if self._rollout_runner is None:
             return optimizer.step()
 
-        next_version = self.policy_version + 1
-        result = self._rollout_runner.apply_weight_update(next_version, optimizer.step)
+        # None lets the scheduler derive live+1 under the policy lock,
+        # avoiding a read-compute-write race on policy_version.
+        result = self._rollout_runner.apply_weight_update(None, optimizer.step)
         self._rollout_runner.step()
         return result