fix(report): load_run_by_id returns NoRuns when no runs match ID

[rocketman-code]

In load_run_by_id (src/report.rs), when matching.is_empty(), the error returned is NoRuns -- but this is semantically imprecise. There are runs, just none matching the requested run ID.

Consider a dedicated error variant (e.g. RunNotFound(String)) or a more specific message. This is pre-existing behavior, not introduced by any recent PR.