fix(backtest): adopt complete CN calendar pin

[Pigbibi]

Problem

The cn_chinext_tactical_rotation lifecycle preflight failed on 2023-06-22 because the locked QPK calendar did not include 2023 CN equity closures. The backtest therefore inserted a synthetic market day with no quote and correctly rejected held-asset valuation.

Change

• Adopt QPK merge 4664c2b283e9409a7dae4febf8571260c9f72724, which adds the complete verified 2023 SSE/SZSE closure dates.
• Update the active dependency, qsl.toml, lockfile, workflow inputs, and compatibility metadata to that exact QPK revision.
• Add regressions proving 2023-06-22/23 are not inserted and that a genuinely missing price on a held asset still raises the existing finite-positive-price error.

The reindex and missing-price protections are unchanged. This PR does not modify quant-monitor, dispatch workflows, collect real market data, or place trades.

Validation

• PYTHONPATH=/tmp/qpk-cn-calendar-merged/src:src python3 -m pytest -q tests/test_proxy_backtest.py tests/test_qsl_compat_metadata.py -k 'not research_extra_installs_frozen_sdk_and_consumer_checker' — 36 passed, 1 deselected
• QPK pin consistency check against 4664c2b283e9409a7dae4febf8571260c9f72724 — passed
• python3 -m pip check — passed
• git diff --check — passed

The local environment lacks ai_gateway_client, so the research-extra installation test was left to CI.