test(data-plane): move data_plane unit tests under tests/unit/ for CI discovery

tests/unit/L0_Unit_Tests_*.sh hard-code TEST_PATHS=('unit/'), so any test outside tests/unit/ is silently skipped. Our data_plane suite lived at tests/data_plane/unit/ and was never collected by CI.

Move all 19 unit tests + conftest + __init__ into tests/unit/data_plane/ via git mv (one was untracked, so plain mv). The tests/data_plane/functional/ tree stays where it is — those are Tier 2 (Ray + TQ), need a separate runner.

Plus three drive-by fixes flagged by CI lint:

- nemo_rl/data_plane/docs/data_plane_api_lifecycle.md → data-plane-api-lifecycle.md (new pre-commit hook disallows underscores in .md filenames).
- nemo_rl/data_plane/column_io.py:158: change variable annotation Mapping -> dict so pyrefly accepts the dict-comp result at the pack_jagged_fields call site (the function signature is dict[str, ...]). Mapping import drops as unused; ruff auto-fixes.
- nemo_rl/data_plane/worker_mixin.py:224,249: pyrefly no-matching-overload on list(meta.fields) where meta.fields: list[str] | None. Use # type: ignore[no-matching-overload] rather than list(meta.fields or []) — the runtime contract guarantees meta.fields is non-None at these call sites; silently substituting [] would mean fetch-nothing which is wrong.
- nemo_rl/experience/sync_rollout_actor.py: add 'import torch' (F821 — module used torch.zeros_like and isinstance(v, torch.Tensor) without importing torch).

Signed-off-by: Zhiyu Li <zhiyul@NVIDIA.com>

Author: ZhiyuLi-Nvidia

nemo_rl/data_plane/column_io.py

@@ -29,7 +29,7 @@
     :class:`KVBatchMeta`.
 """
 
-from typing import Any, Mapping, Sequence
+from typing import Any, Sequence
 
 import numpy as np
 import torch
@@ -155,7 +155,7 @@ def kv_first_write(
             f"kv_first_write: keys ({len(keys)}) must match batch size ({n})"
         )
     lengths = final_batch_cpu["input_lengths"]
-    fields: Mapping[str, torch.Tensor | np.ndarray] = {
+    fields: dict[str, torch.Tensor | np.ndarray] = {
         k: v
         for k, v in final_batch_cpu.items()
         if isinstance(v, torch.Tensor)

…a_plane/docs/data_plane_api_lifecycle.md …a_plane/docs/data-plane-api-lifecycle.mdnemo_rl/data_plane/docs/data_plane_api_lifecycle.md renamed to nemo_rl/data_plane/docs/data-plane-api-lifecycle.md nemo_rl/data_plane/docs/data_plane_api_lifecycle.md renamed to nemo_rl/data_plane/docs/data-plane-api-lifecycle.md

@@ -221,7 +221,7 @@ def _fetch(
                 td = self._require_dp_client().kv_batch_get(
                     keys=meta.keys,
                     partition_id=meta.partition_id,
-                    select_fields=list(meta.fields),
+                    select_fields=list(meta.fields),  # type: ignore[no-matching-overload]
                 )
                 data = materialize(
                     td,
@@ -246,7 +246,7 @@ def _fetch(
         td = self._require_dp_client().kv_batch_get(
             keys=meta.keys,
             partition_id=meta.partition_id,
-            select_fields=list(meta.fields),
+            select_fields=list(meta.fields),  # type: ignore[no-matching-overload]
         )
         data = materialize(
             td,

nemo_rl/data_plane/worker_mixin.py

@@ -40,6 +40,7 @@
 
 import numpy as np
 import ray
+import torch
 
 from nemo_rl.data_plane.column_io import kv_first_write
 from nemo_rl.data_plane.interfaces import KVBatchMeta