RCBC-542: Forward CAS to C++ Core in Append/Prepend

[DemetrisChr]

Motivation

The CAS option was being ignored in the append & prepend operations, and not being passed on to the C++ core.

Changes

• Include the CAS in the core request, if provided.
• Add tests for append/prepend with bad CAS

[Copilot]

Pull request overview

This PR fixes CAS handling for binary append/prepend by ensuring the CAS option is forwarded from the Ruby layer into the C++ core request, and adds regression tests for CAS mismatch behavior.

Changes:

• Forward cas from Ruby options into core::operations::{append,prepend}_request.
• Add tests asserting append/prepend raise Couchbase::Error::CasMismatch when given a bad CAS.
• Pin development OpenTelemetry gem versions in Gemfile.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
ext/rcb_crud.cxx	Adds cb_extract_cas(req, options) to append/prepend backend operations so CAS is included in core requests.
test/crud_test.rb	Adds regression tests for CAS mismatch on binary append/prepend.
Gemfile	Pins opentelemetry-metrics-sdk and opentelemetry-sdk versions for development.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

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