Add benchmark tests and optimize database performance

- Introduced benchmark tests for various database operations, including event saving, querying, and fetching by serials, to assess performance.
- Implemented optimizations to reduce memory allocations and improve efficiency by pre-allocating slices and maps in critical functions.
- Enhanced the `FetchEventsBySerials`, `GetFullIdPubkeyBySerials`, and `QueryForIds` methods with pre-allocation strategies to minimize reallocations.
- Documented performance improvements in the new PERFORMANCE_REPORT.md file, highlighting significant reductions in execution time and memory usage.
- Bumped version to v0.23.1 to reflect these changes.

pkg/database/fetch-events-by-serials.go

@@ -13,7 +13,8 @@ import (
 // FetchEventsBySerials fetches multiple events by their serials in a single database transaction.
 // Returns a map of serial uint64 value to event, only including successfully fetched events.
 func (d *D) FetchEventsBySerials(serials []*types.Uint40) (events map[uint64]*event.E, err error) {
-	events = make(map[uint64]*event.E)
+	// Pre-allocate map with estimated capacity to reduce reallocations
+	events = make(map[uint64]*event.E, len(serials))
 	
 	if len(serials) == 0 {
 		return events, nil