Extract local Symphony release bundle

[nickbeau]

Detail: Download and extract the selected release bundle into the instance runtime cache.

Milestone: Sprint 7: Local Process Runner

Source: docs/technical.md sprint plan.

[nickbeau]

I’m implementing issue #64 now: adding release bundle download/extract support into a local runtime cache path with cache lookup and manifest persistence. I’ll report back with the exact files/behavior before creating the PR.

[nickbeau]

Update: I found an existing local release cache implementation draft in the worktree and am completing it by wiring DI/host registration and adding focused integration tests for download, extraction, runtime copy, and cache reuse. Build was clean before these additions; I’m running targeted and full validation next.