The crate is the per-node metrics/logging pipe with a universal
subscriber endpoint, but "datastream" kept getting misread as a general
messaging plane. Rename crate, module paths, and public API
(`DatastreamEndpoint` → `TelemetryEndpoint`, etc.) so misuse is visible
on sight.
Renamed contracts (all in-repo producers/consumers migrated):
- env vars `MYELIN_DATASTREAM_*` → `MYELIN_TELEMETRY_*`
- artifact `datastream.ndjson` → `telemetry.ndjson`
- actor names `telemetry-publisher` / `telemetry-sink`
- wire ALPN `swactor/telemetry/0`
- `DATASTREAM_SPEC.md` → `TELEMETRY_SPEC.md`
Also fixes two latent test breaks: `process` and `iroh-driver` tests
imported `DatastreamEvent` from the crate root, which was never
re-exported; they now use the observer path `telemetry::frame::`.
Remove the datastore crate, the top-level design/orchestration/ring specs, the
benches, and the ci config. Add the dashboard host telemetry sampler
(cpu/disk/net/gpu/mem). Localize the pipeline-parallel e2e stub/mock paths.
Signed-off-by: Zachery Aaron Shores-Chmielewski <zacheryasc@gmail.com>
