Allow CacheBox 6 for Windows ARM64 support

[contentis]

Summary

• Widen the supported CacheBox range from >=5.2,<6 to >=5.2,<7.
• Update the lockfile to CacheBox 6.2.6.

Testing

• Verified CacheBox 6.2.6 imports successfully under native Windows ARM64 Python 3.12.
• Cache-focused tests: 7 passed, 2 skipped.
• Remaining suite: 1,261 passed, 45 skipped, with two unrelated Windows-specific tests deselected.