Build each object's dependencies, not every object's

The deps artifact was one derivation for the whole workspace, and the
sharing was the point: three objects, one dependency build. What it cost
stayed invisible until a consumer wanted only some of them.

jolt-moq brings moq-net, iroh, quinn, rustls and aws-lc-sys behind it. A
build of libvidya alone still paid for all of it -- and a client that has
stopped loading libjoltmoq paid for it too, which is the case that made
this worth splitting. frq is that client now: its media plane is jolt over
libmoq_ffi, libopus and openh264, and it takes only libvidya and
libjolttui from here.

    whole workspace lock   810 crates
    vidya + tui             146
    no longer built         394

Split by CONSUMER rather than per package. vidya and tui share nearly
everything, so an artifact each would trade one kind of waste for another;
two groups is where the line actually falls.

The workspace-wide artifact stays for clippy and the test run, which do
build everything and do want the sharing this gives up.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>