fix(dataprotection): validate restored PV provenance before completion

[leon-ape]

Part 4 of 4 for #10755.

Problem

An already-bound target PVC was accepted as restore output without checking whether its PV was actually rebound by VolumePopulator.

Changes

• validate an existing target binding before changing the helper PV
• validate the target PV exists through the controller's cached client
• validate ClaimRef namespace/name and UID identify the target PVC
• validate the existing PV populate-from annotation matches the target dataSourceRef
• requeue transient cache lookup gaps; reject definitively foreign bindings before helper cleanup
• validate that a PV still belongs to the helper PVC immediately before rebinding it
• use optimistic locking so a concurrent ClaimRef change is not overwritten

Scope

This is minimum rebind validation only. It does not add provisioner compatibility detection, attempt identity, legacy restore adoption, Cluster finalizers, cleanup refactoring, or workload changes. It performs no uncached reads.

Tests

• full controllers/dataprotection suite
• focused valid/foreign/missing-PV, cache-ordering, helper-preservation, rebind ownership, and concurrent-change tests

Fixes #10755

[apecloud-bot]

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[codecov]

Codecov Report

❌ Patch coverage is 69.92481% with 40 lines in your changes missing coverage. Please review.
✅ Project coverage is 64.92%. Comparing base (6d7846f) to head (237520f).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
...llers/dataprotection/volumepopulator_controller.go	69.92%	27 Missing and 13 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10778      +/-   ##
==========================================
+ Coverage   64.86%   64.92%   +0.05%     
==========================================
  Files         506      506              
  Lines       63300    63428     +128     
==========================================
+ Hits        41058    41178     +120     
- Misses      18603    18604       +1     
- Partials     3639     3646       +7     

Flag	Coverage Δ
unittests	64.92% <69.92%> (+0.05%)	⬆️

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