Update DuckDB to 1.5.0+, Run each benchmark query in its own job for OOM resilience (#93)

* Run each benchmark query in its own job for OOM resilience

- Remove DuckDB <1.5.0 version cap so nightlies resolve to 1.5.x+
- Default DuckDB and SedonaDB to stable releases (nightly opt-in)
- Default scale factors to SF1,SF10 with 600s per-query timeout
- Run each query as a separate GitHub Actions job so OOM on one
  query does not block remaining queries
- Cache pip dependencies across per-query jobs for faster setup
- Summarize script merges per-query result files, fills missing
  engines/queries as not_started (OOM), and shows partial results

* Show completed query count in Performance Summary table

Author: jiayuasu