Hosted storyboard history: represent incomplete fixture coverage separately from executed passes #8416

Observed behavior

A full reporting run against a native catalog without the optional feature returns an explicit coverage_gaps[].reason: fixture_unsatisfied with zero authored reporting steps. The SDK's raw overall_passed boolean can still be true because no executed assertion failed. Addie's existing history writer stores that boolean and counts without a separate incomplete-coverage state; the manual matrix's clean count similarly means no failed rows, not tested feature support.

#8336 fixes Addie's visible report to show Incomplete — coverage gap and Not applicable for this run, while preserving actual SDK results, existing history fields and floor accounting. Training CLI now prints the real coverage-gap detail. No missing native fixture is treated as proof of nonsupport or as an executed reporting pass.

Follow-up: give hosted run history/aggregate presentation a reviewed representation of incomplete fixture coverage, retaining original failure evidence and distinguishing a completed no-match from discovery/schema/protocol errors. Preserve immutable historical records; do not backfill invented support, globally skip mandatory failures or silently lower grading floors. A failed selected implementation must stay failed even when another scope is unexercised.

This host accounting/presentation follow-up is separate from catalog selection and the per-invocation reporting adapter; no evaluator/registry policy implementation or release is assigned by this issue.