fix(examples): with-telemetry.yaml references retired clockreceiver + stdoutexporter (RFC-0013 cleanup)

[trilamsr]

Problem

Surfaced during PR #453 review: `docs/examples/with-telemetry.yaml` fails `tracecore validate` against the OCB binary because it still references components retired by RFC-0013:

• `clockreceiver`
• `stdoutexporter`

Reproduced on main via `git stash` — pre-existing, unrelated to #443.

Scope

Replace the retired references with their RFC-0013 successors (or remove the example if obsolete). Confirm `tracecore validate docs/examples/with-telemetry.yaml` exits 0 after.

Refs

PR #453, RFC-0013.