v0.6.8-shardfix baseline

Baseline shard/save-state Windows candidate.

Code baselines:

• MetroidPrimeHuntersRecomp main: 4cd9d38
• ndsrecomp main: 6fcd821

Validated before upload:

• live_overlay_preflight_test.exe passed
• tools/test_build_release_shard_cache.py passed
• PYTHONPATH=tools python tools/test_shard_performance_gate.py passed
• Basic shard validation passed with cold runtime TCC generation and warm prebuilt GCC shard hits
• Save-state focused tests passed in the local candidate build

ZIP SHA256:
A5DD8B77D57F1B1FB7551BD3B8E4115855E0034E061438BB2694C88F8DC5FA2B