fix(eventstore): use decimal, correct mirror (#9916)

# Eventstore fixes

- `event.Position` used float64 before which can lead to [precision
loss](https://github.com/golang/go/issues/47300). The type got replaced
by [a type without precision
loss](https://github.com/jackc/pgx-shopspring-decimal)
- the handler reported the wrong error if the current state was updated
and therefore took longer to retry failed events.

# Mirror fixes

- max age of auth requests can be configured to speed up copying data
from `auth.auth_requests` table. Auth requests last updated before the
set age will be ignored. Default is 1 month
- notification projections are skipped because notifications should be
sent by the source system. The projections are set to the latest
position
- ensure that mirror can be executed multiple times

internal/database/database.go

@@ -64,6 +64,10 @@ func CloseTransaction(tx Tx, err error) error {
 	return commitErr
 }
 
+const (
+	PgUniqueConstraintErrorCode = "23505"
+)
+
 type Config struct {
 	Dialects  map[string]interface{} `mapstructure:",remain"`
 	connector dialect.Connector

internal/database/dialect/connections.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"reflect"
 
+	pgxdecimal "github.com/jackc/pgx-shopspring-decimal"
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgtype"
 )
@@ -23,7 +24,12 @@ type ConnectionConfig struct {
 	AfterRelease  []func(c *pgx.Conn) error
 }
 
-var afterConnectFuncs []func(ctx context.Context, c *pgx.Conn) error
+var afterConnectFuncs = []func(ctx context.Context, c *pgx.Conn) error{
+	func(ctx context.Context, c *pgx.Conn) error {
+		pgxdecimal.Register(c.TypeMap())
+		return nil
+	},
+}
 
 func RegisterAfterConnect(f func(ctx context.Context, c *pgx.Conn) error) {
 	afterConnectFuncs = append(afterConnectFuncs, f)