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/extension/backend/swiglu.py

@@ -40,6 +40,11 @@ def _swiglu_capable(x: Tensor, up_weight: Tensor, gate_weight: Tensor) -> bool:
         or not x.is_contiguous()
         or not up_weight.is_contiguous()
         or not gate_weight.is_contiguous()
+        # The fused kernel reads all streams as uint4; contiguous-but-offset
+        # views are routed to the unfused chain instead of failing.
+        or (x.data_ptr() & 15) != 0
+        or (up_weight.data_ptr() & 15) != 0
+        or (gate_weight.data_ptr() & 15) != 0
         or not is_available("bf16_swiglu")
     )