[improvement](cloud) Add V2 delete bitmap consistency checks

[wyxxxcat]

What problem does this PR solve?

Issue Number: close #xxx

Related PR: #xxx

Problem Summary:
The Cloud Recycler checker did not validate V2 delete bitmap metadata against active rowsets and object storage, allowing missing, orphaned, or inconsistent delete bitmap data to go undetected.

This change adds independent checks for FDB, standalone-file, and packed-file storage. It also validates packed-file slice locations, resource ownership, reverse references, and reference counts, with focused CheckerTest coverage.

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[hello-stephen]

Thank you for your contribution to Apache Doris.
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Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[wyxxxcat]

run buildall

[hello-stephen]

Cloud UT Coverage Report

Increment line coverage 63.65% (338/531) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	78.35% (2070/2642)
Line Coverage	66.03% (37914/57422)
Region Coverage	53.31% (35501/66589)
Branch Coverage	56.70% (11402/20108)