Decouple ASAPQuery-backend from ASAPCollector as a build dependency

[milindsrivastava1997]

Why

ASAPQuery-backend currently requires an ASAPCollector checkout/source for build-time dependencies, even though the asapquery profile is intended to run without a Collector service.

The direct dependency paths are:

• data_plane depends on Collector’s Git-sourced asap-precompute-rs; its relative asap_sketchlib dependency requires the workspace Cargo patch.
• gorilla-merger replaces github.com/ProjectASAP/asap-gorilla-go with ../../ASAPCollector/asap-gorilla-go because the needed intchunk subpackage is not in the published tag.
• The Rust/Go dependency paths flow into Docker build contexts, setup documentation, and the optional system E2E harness.

What to build

Make ASAPQuery-backend build and run its standalone compatibility profile without a sibling ASAPCollector checkout or an ASAPCollector Git dependency. Consume independently versioned/published shared components, or move the narrow functionality owned by this backend into an appropriate independent package. Keep Collector integration an explicit optional integration concern.

Acceptance criteria

• A clean clone of ASAPQuery-backend builds its Rust workspace and gorilla-merger without an ASAPCollector checkout.
• Cargo manifests and lockfile do not resolve packages from the ASAPCollector repository.
• gorilla-merger no longer uses a local replacement into ../../ASAPCollector.
• Backend Docker builds do not require ASAPCollector build contexts.
• Standalone setup and compatibility-profile verification do not instruct users to clone ASAPCollector; the optional cross-repo system harness remains explicitly documented if retained.
• Focused build/compatibility coverage verifies the standalone dependency boundary.

Blocked by

None - can start immediately