fix(eventstore): use decimal, correct mirror (#9905)

back port #9812, #9878, #9881, #9884

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>
Co-authored-by: Stefan Benz <46600784+stebenz@users.noreply.github.com>

internal/eventstore/event.go

@@ -5,6 +5,8 @@ import (
 	"reflect"
 	"time"
 
+	"github.com/shopspring/decimal"
+
 	"github.com/zitadel/zitadel/internal/zerrors"
 )
 
@@ -44,7 +46,7 @@ type Event interface {
 	// CreatedAt is the time the event was created at
 	CreatedAt() time.Time
 	// Position is the global position of the event
-	Position() float64
+	Position() decimal.Decimal
 
 	// Unmarshal parses the payload and stores the result
 	// in the value pointed to by ptr. If ptr is nil or not a pointer,