Enable Java 25 virtual threads in NVCF Java services

Description

Enable Java 25 virtual threads in eligible NVCF Java services after the Spring Boot 4.1.1 framework and service upgrades tracked by #1150.

Use a controlled rollout. Identify request paths and executors that benefit from virtual threads, preserve bounded concurrency where it provides backpressure, validate the required Java 25 runtime fix, and make the change reversible through configuration.

Definition of Done

• Identify the Java services, request paths, and executors eligible for virtual threads.
• Confirm build images, runtime images, and Bazel toolchains use a supported Java 25 release containing the required virtual-thread fix.
• Enable virtual threads through service configuration without replacing bounded executors that enforce concurrency or resource limits.
• Add or update tests for configuration, request execution, shutdown, timeout, and cancellation behavior.
• Validate affected services in supported managed and self-hosted environments.
• Confirm logging, tracing, security context, and request context propagate correctly across virtual threads.
• Provide a per-service enable/disable control and a documented rollback procedure.
• Update Helm charts, component versions, and configuration defaults after validation.
• Observe a non-production rollout and document the production promotion criteria.

Resources (optional)

• #1150
• #1162

By submitting this issue, you acknowledge that you are an assigned member of the NVCF development team and agree to follow our code of conduct and our contributing guidelines.

Start by reading the dependency on #1150 and the related resource #1162, then identify the Java services, request paths, executors, build and runtime images, Bazel toolchains, and Helm charts involved. Validate Java 25 support and the configuration, execution, shutdown, timeout, cancellation, and context-propagation requirements. Done means controlled per-service rollout and rollback controls, updated tests and defaults, environment validation, and documented promotion criteria.