Remove legacy code

[milindsrivastava1997]

• CircularBuffer cleanup policy in asap-query-engine store
• Once Support sliding window candidates in the query engine (execution) #557 instant-query/range-query unification ships (Sliding's instant path reuses the range-query pipeline's stride-W walk instead of a dedicated exact-match lookup), query_precomputed_output_exact / StoreQueryParams::is_exact_query: true becomes unused — nothing will set is_exact_query: true anymore.