fix: use correct hash value from label anno manager

[AnnaYue]

修复 IsTargetPvcTmpChanged 方法中 PVC hash 值获取逻辑：

• 使用 setLabelAnnoMgr.Get() 返回的值而非直接读取 pvc.Labels
• 移除未使用的 appsv1alpha1 import

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

2. What is the scope of this PR (e.g. component or file name):

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
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• Manual test (add detailed scripts or steps below)
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6. Release note

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None

[Copilot]

Pull request overview

This PR fixes PVC template-hash retrieval in IsTargetPvcTmpChanged by consistently using the XSetLabelAnnotationManager abstraction (instead of reading raw pvc.Labels), and cleans up an unused import.

Changes:

• Read PVC template-hash via pc.xsetLabelAnnoMgr.Get(..., api.SubResourcePvcTemplateHashLabelKey) and store that value for comparisons.
• Remove unused appsv1alpha1 import from subresources/pvc_control.go.

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[Copilot]

IsTargetPvcTmpChanged ignores the exist boolean when reading XInstanceIdLabelKey for both the PVC and the target. If either label is missing, both IDs default to "" and the code can incorrectly treat unrelated PVCs as belonging to the target, leading to wrong hash comparisons. Consider fetching targetId once (with an exist check; if missing, return early) and only comparing PVCs whose instance-id label exists and matches.

[ColdsteelRail]

lgtm