chore(build): Update snap packaging to use prebuilt binaries

Problem Statement

We want to use identical binaries across all the packaging systems, reusing same hashes, etc. We can update snapcraft.yaml to use prebuilt binaries built by earlier stages of the pipeline.

Proposed Design

We can update the snapcraft.yaml to use the dump plugin to assemble the file system of the snap from binaries that exist in the target/ directory. The CI pipeline can then reuse binaries built by earlier jobs and transfer them, as artifacts, into the job that calls snapcraft pack

Alternatives Considered

Making identical builds (reproducible builds) is possible but would not avoid cost of building on every merge.

Agent Investigation

No response

Checklist

• I've reviewed existing issues and the architecture docs
• This is a design proposal, not a "please build this" request

Start with snapcraft.yaml and inspect how the current snap is assembled, then trace the CI pipeline stages that produce target/ and the job that runs snapcraft pack. Update the packaging flow so those earlier-built binaries are transferred as artifacts and used to assemble the snap; done means the snap uses the prebuilt binaries and preserves their hashes.