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/repository/event.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/shopspring/decimal"
 	"github.com/zitadel/logging"
 
 	"github.com/zitadel/zitadel/internal/eventstore"
@@ -22,7 +23,7 @@ type Event struct {
 	// Seq is the sequence of the event
 	Seq uint64
 	// Pos is the global sequence of the event multiple events can have the same sequence
-	Pos float64
+	Pos decimal.Decimal
 
 	//CreationDate is the time the event is created
 	// it's used for human readability.
@@ -97,7 +98,7 @@ func (e *Event) Sequence() uint64 {
 }
 
 // Position implements [eventstore.Event]
-func (e *Event) Position() float64 {
+func (e *Event) Position() decimal.Decimal {
 	return e.Pos
 }