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_base.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/shopspring/decimal"
 	"github.com/zitadel/logging"
 
 	"github.com/zitadel/zitadel/internal/api/authz"
@@ -25,7 +26,7 @@ type BaseEvent struct {
 	Agg *Aggregate
 
 	Seq                           uint64
-	Pos                           float64
+	Pos                           decimal.Decimal
 	Creation                      time.Time
 	previousAggregateSequence     uint64
 	previousAggregateTypeSequence uint64
@@ -38,7 +39,7 @@ type BaseEvent struct {
 }
 
 // Position implements Event.
-func (e *BaseEvent) Position() float64 {
+func (e *BaseEvent) Position() decimal.Decimal {
 	return e.Pos
 }