B4: extend smoke-dev.sh to cover the provider path

Extend `scripts/smoke-dev.sh` to cover the provider path now that providers exist, so the check is meaningful rather than a cloud-plane-only smoke test.

### Add
- Provider count and trust level per provider
- One real streaming completion, asserting tokens arrive and the stream terminates cleanly
- A billing debit assertion (balance moves by a plausible amount)
- Release lookup (`/v1/releases/latest`) resolving to the dev host

The script is already built to exit non-zero so a calling job can alert, and it already refuses to run against production keys. Keep both properties.

### Acceptance criteria
- [ ] `smoke-dev.sh` passes against the dev environment
- [ ] Fails loudly when a provider is absent or a completion stalls
- [ ] Wired into the deploy pipeline or a schedule (whichever A8's decision implies)

Start with scripts/smoke-dev.sh and trace its existing cloud-plane checks and non-zero exit behavior. Add coverage for provider counts and trust levels, streaming completion termination, billing balance changes, and /v1/releases/latest resolving to the dev host. Verify the script fails for missing providers or stalled completions, then determine pipeline or schedule wiring from A8's decision.

Written by the indexing model from the issue text.