csi: watch VGRC metadata to reduce memory usage

[iPraveenParihar]

Describe what this PR does

Use WatchesMetadata instead of caching full VolumeGroupReplicationContent objects in the informer cache. This reduces memory consumption in clusters with many VGRC objects by only caching object metadata.

Also adds a delete event predicate filter to skip unnecessary reconciliation for objects being deleted.

Fixes: #5414

Future concerns

List items that are not part of the PR and do not impact it's
functionality, but are work items that can be taken up subsequently.

Checklist:

• Commit Message Formatting: Commit titles and messages follow guidelines in the developer guide.
• Reviewed the developer guide on Submitting a Pull Request
• Pending release notes updated with breaking and/or notable changes for the next major release.
• Documentation has been updated, if necessary.
• Unit tests have been added, if necessary.
• Integration tests have been added, if necessary.

---

Show available bot commands

These commands are normally not required, but in case of issues, leave any of
the following bot commands in an otherwise empty comment in this PR:

• /retest ci/centos/<job-name>: retest the <job-name> after unrelated
  failure (please report the failure too!)

[black-dragon74]

You need to add VRGC to:

ceph-csi/internal/controller/controller.go

Lines 85 to 88 in 62342db

	DisableFor: []client.Object{
	&corev1.PersistentVolume{},
	&corev1.Secret{},
	},

If missing, a duplicate cache will be created on Get()

[iPraveenParihar]

@Mergifyio rebase

[mergify]

rebase

🛑 The pull request rule doesn't match anymore

Details

This action has been cancelled.

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Deprecation notice: This pull request comes from a fork and was queued with update_method=rebase and update_bot_account impersonation. This capability will be removed on July 1, 2026. After this date, the merge queue will no longer be able to rebase fork pull requests with this configuration. To avoid disruption, switch to update_method=merge in your queue rule.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-06-23 03:59 UTC · Rule: default · triggered by merge protections
• ✅ Checks passed · in-place
• ✅ Merged — 2026-06-23 04:34 UTC · at 1749f471c1d4d7fd7c411a4937c66dad4162504a · rebase

This pull request spent 34 minutes 47 seconds in the queue, including 34 minutes 10 seconds running CI.

Required conditions to merge

• #approved-reviews-by >= 2 [🛡 GitHub branch protection]
  • csi: watch VGRC metadata to reduce memory usage #6345