[BUG] 在 0.37.0 中, lossless_only 被接受但无效 — SmartCrusher 会将数组项丢弃到 max_items_after_crush, 而不会添加 CCR 标记

Summary In 0.37.0, SmartCrusherConfig.lossless_only is accepted by both the Python wrapper and the PyO3 config, but has no effect: the output is byte-identical with the flag on and off. On a JSON object whose value is an array, the crusher drops items down to max_items_after_crush (default 15) and emits no CCR marker, so a consumer has no way to detect that content was removed — and no configuration produces marker-free and complete output. This is the guarantee #1091 was closed by introducing, and it is a different failure from #1478 (there, the Rust struct rejected the kwarg with a TypeError; here it accepts it and ignores it). ## Reproduce Python import json from headroom._core import SmartCrusher, SmartCrusherConfig data = json.dumps({"slugs": [f"r{i}" for i in range(53)]}) for cfg in (dict(lossless_only=True), dict(lossless_only=False), dict(lossless_only=True, enable_ccr_marker=True), dict(lossless_only=True, enable_ccr_marker=False)): out = SmartCrusher(SmartCrusherConfig(**cfg)).crush(data, "", 1.0).compressed print(f"{str(cfg):58} -> slugs {len(json.loads(out)['slugs']):2}/53 " f"ccr_marker={'<<ccr:' in out}") {'lossless_only': True} -> slugs 15/53 ccr_marker=False {'lossless_only': False} -> slugs 15/53 ccr_marker=False {'lossless_only': True, 'enable_ccr_marker': True} -> slugs 15/53 ccr_marker=False {'lossless_only': True, 'enable_ccr_marker': False} -> slugs 15/53 ccr_marker=False The package's own Python wrapper behaves identically, so this is not a matter of bypassing it: Python wrapper lossless_only=True slugs 53 -> 15 ccr_marker=False bytes 372 -> 91 Python wrapper lossless_only=False slugs 53 -> 15 ccr_marker=False bytes 372 -> 91 Python wrapper output identical for True/False: True _core (PyO3) lossless_only=True slugs 53 -> 15 ccr_marker=False bytes 372 -> 91 _core (PyO3) lossless_only=False slugs 53 -> 15 ccr_marker=False bytes 372 -> 91 _core (PyO3) output identical for True/False: True ## Expected Per the crush() docstring in headroom/transforms/smart_crusher.py, with lossless_only=True "rows are never dropped and opaque cells render inline", and the output is byte-recoverable. Either that, or the row-drop path should emit the CCR marker that enable_ccr_marker=True promises — the current behaviour offers neither. ## Impact (measured) We run an LLM job scheduler that compresses large command stdout before it reaches the model, using the native primitives directly (lossless_only=True, CCR disabled — we never want a retrieval round-trip). Because we did not trust the flag, every candidate is validated by an independent JSON-equivalence check before it is allowed to replace the original, and rejected results fall back to the uncompressed output. Over one week across ~30 agents: **260 compressions were rejected…