Extract Flask apps and Docker deployment into a separate server repository #3741

Part of #3737.

Blocked by #3739 and #3740.

Move the Flask implementation and container deployment to a new repository once the reusable contract suite and supported core interface are available. The new repository's name is to be decided.

Acceptance criteria:

• Move the VWS/VWQ Flask apps, target-manager service, health checks, Dockerfiles/build configuration, Flask/deployment-specific tests, image release workflows, and deployment documentation.
• Depend on vws-python-mock at runtime through its supported interface. Consume the shared contract suite as a development dependency, pinned to a compatible revision; do not copy its assertions.
• Supply server-owned pytest adapters for Flask in-process and actual container deployments. Run applicable shared tests against both, preserving documented transport differences such as malformed Content-Length handling.
• Preserve the three-service deployment and verify database setup, signed VWS requests, upload/processing, queries, report download URLs, health checks, restarts/state persistence, and cleanup through actual deployments.
• Retain meaningful coverage gates for code owned by each repository. Update core CI partitions, package manifests, dependency ownership, documentation, and release workflows after removing server-owned files.
• Pin compatible core and contract-suite revisions and update them through normal PRs. Add a scheduled compatibility run against core main to detect upcoming changes.
• Preserve published image names/targets and environment-variable behavior where practical; provide a clear migration for any changed image references, commands, or documentation links.
• Document installation, local development, contract-suite invocation, and release ownership in the new repository. Verify built packages and container images before considering the extraction complete.

Completion point: the independently released server passes the shared suite and deployment checks, and the core repository no longer owns its Flask/Docker implementation.

Related: #3724 tracks a deployment launcher that consumes published images. This extraction preserves that separate launcher scope.