CBG-4232 uptake rosmar hierarchical subdoc support

[torcolvin]

CBG-4232 uptake rosmar hierarchical subdoc support

Uses couchbaselabs/rosmar#69

Dependencies (if applicable)

• Link upstream PRs
• Update Go module dependencies when merged

Do not merge until upstream PR is merged and go.mod is updated.

[Copilot]

Pull request overview

Updates Sync Gateway’s Rosmar dependency to pick up hierarchical subdoc support and enables previously CBS-only tests to run under Rosmar (while still skipping the subset that truly requires the gocb DCP client).

Changes:

• Bump github.com/couchbaselabs/rosmar to a newer pseudo-version that includes hierarchical subdoc support.
• Remove UnitTestUrlIsWalrus() skips from attachment compaction and metadata/subdoc tests so they run in Rosmar.
• Replace some ErrXattrNotFound assertions with base.RequireXattrNotFoundError, and gate rollback/DCP-client-specific tests with base.TestRequiresGocbDCPClient.

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
rest/attachmentcompactiontest/attachment_compaction_api_test.go	Removes Walrus skips for attachment compaction API tests; explicitly skips the rollback test that requires gocb DCP client.
db/attachment_compaction_test.go	Enables attachment compaction unit tests under Rosmar; improves xattr-not-found assertions; uses TestRequiresGocbDCPClient where appropriate.
base/collection_xattr_test.go	Enables metadata store subdoc/xattr tests under Rosmar now that hierarchical subdoc support is available.
go.mod	Updates the Rosmar dependency version.
go.sum	Adds checksums for the new Rosmar pseudo-version.