Replace live_routes database table with in-memory routing table

- Remove live_routes table from SQL schema and all related indexes
- Create new internal/routingtable package with thread-safe RoutingTable
- Implement RouteKey-based indexing with secondary indexes for efficient lookups
- Add RoutingTableHandler to manage in-memory routes separately from database
- Update DatabaseHandler to only handle persistent database operations
- Wire up RoutingTable through fx dependency injection
- Update server to get live route count from routing table instead of database
- Remove LiveRoutes field from database.Stats struct
- Update tests to work with new architecture

internal/database/slowquery.go

@@ -26,6 +26,7 @@ func (d *Database) queryRow(query string, args ...interface{}) *sql.Row {
 }
 
 // query wraps Query with slow query logging
+// nolint:unused // kept for future use to ensure all queries go through slow query logging
 func (d *Database) query(query string, args ...interface{}) (*sql.Rows, error) {
 	start := time.Now()
 	defer logSlowQuery(d.logger, query, start)