PromQL planner omits topk over temporal aggregations #699

Problem

Valid PromQL expressions that apply topk to a temporal aggregation are not represented in the generated planner output and cannot be served by ASAPQuery.

Affected expressions include:

topk(1, sum_over_time(data[5m]))
topk by (job) (3, count_over_time(data[5m]))

The planner recognizes topk when its operand is a raw vector selector. Its spatial-over-temporal query patterns cover a limited set of other aggregation operators but do not include topk. As a result, these queries are omitted from inference_config.yaml even though the underlying temporal expressions are planned.

Observed behavior

All 24 topk-over-temporal queries in the aggregations differential suite fail for both range and instant evaluation.

DEBUG logs report:

query=topk(1, sum_over_time(data[5m])) destination=none_unsupported

Because unsupported-query forwarding is disabled in the differential configuration, the public response is:

bad_data: No result for query

The generated inference configuration contains entries for sum_over_time(data[5m]) and count_over_time(data[5m]), but none of the surrounding topk expressions.

Impact

ASAPQuery cannot answer this class of valid PromQL queries locally. The failure is surfaced as a generic missing-result error rather than identifying the unsupported query shape.