* test(integration): move legacy proxy, router and Redis tests into tests/integration
Port 39 legacy tests to the integration tier that owns them, running against
the scripted upstream, local Postgres and Redis, test-owned wire peers and
owned proxies. Delete 5 legacy tests whose contract is already owned by an
existing integration test, and remove the legacy functions, files and helpers
left unused.
* test(integration): cover recovery of a spent key after its budget is raised
