…est fixes

Seven Minor items from the CodeRabbit full-diff re-scan on
commit ``55377e5d``.

**F-#2 — Clarify Mode-A guidance in ``protrain_optimizer_wrapper``
8-bit warning (``api/optim_wrapper.py:802-815``).**

The warning told users to set ``protrain_force_all_persistent: true``
to get end-to-end 8-bit AdamW on CPU-resident chunks, but didn't
mention that ``protrain_force_all_persistent`` is ignored while
``protrain_auto_mode`` is on (the auto-mode selector picks the mode
itself based on capacity). Expanded the warning to instruct users
to set ``protrain_auto_mode: false`` AND
``protrain_force_all_persistent: true`` together.

**F-#4 — Unify fragmentation-alpha docs in DESIGN.md.**

Module summaries at lines 49 (``cost/memory.py``) and 118
(``memory.py`` module spec) still described a fixed ``alpha=1.10``
while Design Decision 1 documents the per-dtype lookup
(``ALPHA_FRAGMENTATION_4BIT = 0.75`` for bnb-4-bit). Aligned both
summaries to reference the per-dtype helper
(``alpha_fragmentation_for_dtype``) and the design decision section.

**F-#5 — Resolve ``use_reentrant`` contradiction in DESIGN.md.**

Line 109 (``block/checkpoint.py`` module spec) said
``use_reentrant=False``, which matches the actual implementation
(verified via ``grep`` against ``block/checkpoint.py:99``). Line 290
(audit Block G analysis) claimed ``use_reentrant=True, the
production wrap`` — stale and incorrect. Updated the analysis text
to acknowledge ``use_reentrant=False`` is the production wrap and
re-stated the per-block-input residual mechanism in a form
compatible with the non-reentrant variant (each CKPT block's
saved-tensors-hooks recompute frame holds the block input, which
is what produces the linear-in-N_block activation footprint the
audit data exposes).

**F-#8 — Centralized CUDA-availability guard in
``tests/protrain/test_adamw8bit_adapter.py::_gpu_device``.**

The helper unconditionally returned ``torch.device("cuda:0")``,
so a custom marker filter or conftest override that lands the
module in a CPU-only context would surface as a torch error
before any test body. Added a
``pytest.skip("CUDA not available; ...")`` early-return so every
gpu-marked test in the module gets a clean skip.

**F-#9 — Replace silent ``try/except: pass`` with
``contextlib.suppress(Exception)`` in
``tests/protrain/test_lora_offload_mode.py``.**

Five sites — lines 742-746, 839-843, 906-910, 981-985, 1040-1044
— each had the same ``for h in handles: try: h.remove() except
Exception: pass`` pattern that Ruff S110 flags. Replaced with
``contextlib.suppress(Exception)`` over the loop. Semantics
unchanged (best-effort cleanup, tolerate already-removed handles
or torch shutting down mid-test); intent now documented by the
context manager.

**F-#10 — ASCII ``x`` in ``test_lora_offload_mode.py:1062`` docstring.**

Missed in the R5 unicode sweep — ``4×3090`` ⇒ ``4x3090``.

**F-#11 — ``try/finally`` for ``wrapped.close()`` in 3 sites of
``test_trace_skip_on_override.py``.**

``test_run_trace_skipped_on_override_full_path`` (L255-282),
``test_run_trace_invoked_without_override`` (L319-337), and
``test_partial_overrides_do_not_skip_trace`` (L381-400) each
called ``wrapped.close()`` only on the success path — assertion
failures earlier in the test body would skip the close and leak
CUDA + chunk resources into subsequent GPU tests. Wrapped each
test body in ``try/finally`` so ``wrapped.close()`` always
runs. Done programmatically via a one-shot Python rewrite
(8 lines of new indent + 2 lines of try/finally per site) to
keep the diff mechanical.

### Test gates

- ``pre-commit run --all-files`` ALL green (ruff / ruff-format /
  mypy / bandit / yaml / eol / whitespace).
- ``tests/protrain/`` default-marker: 313 passed / 4 skipped /
  162 deselected / 0 failed.
- GPU sanity on F-touched files (GPU 5): 43 passed / 2 skipped /
  0 failed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Fixes pre-commit failures on CI after the ARCH #8/#9/#10 commits:
ruff-format auto-format on 8 files (line-wrap of comprehensions and
MagicMock(spec=...) calls; alphabetize one multi-import block;
strip a trailing blank line in a test header) and add the missing
`Any` symbol that `cast("Any", ...)` in test_modec_persistent_partition.py
referenced without import.

…rt-plugin auto_memory

Add two config-completeness guards that mirror commit 342e1bd's
DDP+zero3 validator pattern (detect known-bad composition at config time,
fail or warn loudly with an actionable message).

1. args.py `_guard_lora_mlp_kernel_with_mode_bc` model_validator hard-rejects
   `lora_mlp_kernel: true` combined with `protrain_force_replicated_cpu_offload:
   true` or `protrain_zero3_shard: true` (the v61 LoRA_MLPBackward crash is
   deterministic on Mode-B/C-forced configs) and warns on `protrain_auto_mode:
   true` (searcher might pick Mode B). Closes proposal §6.qq / §16 PR #10.

2. plugin.py `_maybe_warn_inert_plugin` fires a one-shot LOG.warning from
   `pre_model_load` when the plugin is listed but `protrain_auto_memory` is
   falsy — surfaces the inert-plugin failure mode that produced v15-v52's
   vanilla-axolotl "measurements". Module-level flag keeps it idempotent.
   Closes proposal §16 PR #9.

Tests in tests/protrain/test_lora_mlp_kernel_mode_b_validator.py (11 new).

…est fixes

Seven Minor items from the CodeRabbit full-diff re-scan on
commit ``55377e5d``.

**F-#2 — Clarify Mode-A guidance in ``protrain_optimizer_wrapper``
8-bit warning (``api/optim_wrapper.py:802-815``).**

The warning told users to set ``protrain_force_all_persistent: true``
to get end-to-end 8-bit AdamW on CPU-resident chunks, but didn't
mention that ``protrain_force_all_persistent`` is ignored while
``protrain_auto_mode`` is on (the auto-mode selector picks the mode
itself based on capacity). Expanded the warning to instruct users
to set ``protrain_auto_mode: false`` AND
``protrain_force_all_persistent: true`` together.

**F-#4 — Unify fragmentation-alpha docs in DESIGN.md.**

Module summaries at lines 49 (``cost/memory.py``) and 118
(``memory.py`` module spec) still described a fixed ``alpha=1.10``
while Design Decision 1 documents the per-dtype lookup
(``ALPHA_FRAGMENTATION_4BIT = 0.75`` for bnb-4-bit). Aligned both
summaries to reference the per-dtype helper
(``alpha_fragmentation_for_dtype``) and the design decision section.

**F-#5 — Resolve ``use_reentrant`` contradiction in DESIGN.md.**

Line 109 (``block/checkpoint.py`` module spec) said
``use_reentrant=False``, which matches the actual implementation
(verified via ``grep`` against ``block/checkpoint.py:99``). Line 290
(audit Block G analysis) claimed ``use_reentrant=True, the
production wrap`` — stale and incorrect. Updated the analysis text
to acknowledge ``use_reentrant=False`` is the production wrap and
re-stated the per-block-input residual mechanism in a form
compatible with the non-reentrant variant (each CKPT block's
saved-tensors-hooks recompute frame holds the block input, which
is what produces the linear-in-N_block activation footprint the
audit data exposes).

**F-#8 — Centralized CUDA-availability guard in
``tests/protrain/test_adamw8bit_adapter.py::_gpu_device``.**

The helper unconditionally returned ``torch.device("cuda:0")``,
so a custom marker filter or conftest override that lands the
module in a CPU-only context would surface as a torch error
before any test body. Added a
``pytest.skip("CUDA not available; ...")`` early-return so every
gpu-marked test in the module gets a clean skip.

**F-#9 — Replace silent ``try/except: pass`` with
``contextlib.suppress(Exception)`` in
``tests/protrain/test_lora_offload_mode.py``.**

Five sites — lines 742-746, 839-843, 906-910, 981-985, 1040-1044
— each had the same ``for h in handles: try: h.remove() except
Exception: pass`` pattern that Ruff S110 flags. Replaced with
``contextlib.suppress(Exception)`` over the loop. Semantics
unchanged (best-effort cleanup, tolerate already-removed handles
or torch shutting down mid-test); intent now documented by the
context manager.

**F-#10 — ASCII ``x`` in ``test_lora_offload_mode.py:1062`` docstring.**

Missed in the R5 unicode sweep — ``4×3090`` ⇒ ``4x3090``.

**F-#11 — ``try/finally`` for ``wrapped.close()`` in 3 sites of
``test_trace_skip_on_override.py``.**

``test_run_trace_skipped_on_override_full_path`` (L255-282),
``test_run_trace_invoked_without_override`` (L319-337), and
``test_partial_overrides_do_not_skip_trace`` (L381-400) each
called ``wrapped.close()`` only on the success path — assertion
failures earlier in the test body would skip the close and leak
CUDA + chunk resources into subsequent GPU tests. Wrapped each
test body in ``try/finally`` so ``wrapped.close()`` always
runs. Done programmatically via a one-shot Python rewrite
(8 lines of new indent + 2 lines of try/finally per site) to
keep the diff mechanical.

### Test gates

- ``pre-commit run --all-files`` ALL green (ruff / ruff-format /
  mypy / bandit / yaml / eol / whitespace).
- ``tests/protrain/`` default-marker: 313 passed / 4 skipped /
  162 deselected / 0 failed.
- GPU sanity on F-touched files (GPU 5): 43 passed / 2 skipped /
  0 failed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Fixes pre-commit failures on CI after the ARCH #8/#9/#10 commits:
ruff-format auto-format on 8 files (line-wrap of comprehensions and
MagicMock(spec=...) calls; alphabetize one multi-import block;
strip a trailing blank line in a test header) and add the missing
`Any` symbol that `cast("Any", ...)` in test_modec_persistent_partition.py
referenced without import.

…rt-plugin auto_memory

Add two config-completeness guards that mirror commit 342e1bd's
DDP+zero3 validator pattern (detect known-bad composition at config time,
fail or warn loudly with an actionable message).

1. args.py `_guard_lora_mlp_kernel_with_mode_bc` model_validator hard-rejects
   `lora_mlp_kernel: true` combined with `protrain_force_replicated_cpu_offload:
   true` or `protrain_zero3_shard: true` (the v61 LoRA_MLPBackward crash is
   deterministic on Mode-B/C-forced configs) and warns on `protrain_auto_mode:
   true` (searcher might pick Mode B). Closes proposal §6.qq / §16 PR #10.

2. plugin.py `_maybe_warn_inert_plugin` fires a one-shot LOG.warning from
   `pre_model_load` when the plugin is listed but `protrain_auto_memory` is
   falsy — surfaces the inert-plugin failure mode that produced v15-v52's
   vanilla-axolotl "measurements". Module-level flag keeps it idempotent.
   Closes proposal §16 PR #9.

Tests in tests/protrain/test_lora_mlp_kernel_mode_b_validator.py (11 new).