test(run-store): remove stale fromShards test after merging main

runOpsStore.fromShards.test.ts imported UnknownShardKey and called
RoutingRunStore.fromShards — both removed in main's RoutingRunStore refactor
(constructor-based shards). The file is unique to this branch and now
references APIs that no longer exist, so it fails the run-store suite. Its
routing coverage lives in main's shardMap/runKeyedRouting/nShardMatrix tests.

Author: d-cs