test: cover before_reset without context engine

[haosenwang1018]

Summary

• add a focused plugin test for before_reset when the OpenViking context-engine was registered but never instantiated
• verify that reset remains a no-op in that case instead of attempting a commit through a missing engine reference
• strengthen the hook/context-engine compatibility coverage around the recent OpenClaw integration fixes

Testing

• git diff --check

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[github-actions]

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[github-actions]

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[qin-ctx]

pr有重复哈，先关闭了