feat: add debug events API (#8533)

# Which Problems Are Solved

Add a debug API which allows pushing a set of events to be reduced in a
dedicated projection.
The events can carry a sleep duration which simulates a slow query
during projection handling.

# How the Problems Are Solved

- `CreateDebugEvents` allows pushing multiple events which simulate the
lifecycle of a resource. Each event has a `projectionSleep` field, which
issues a `pg_sleep()` statement query in the projection handler :
  - Add
  - Change
  - Remove
- `ListDebugEventsStates` list the current state of the projection,
optionally with a Trigger
- `GetDebugEventsStateByID` get the current state of the aggregate ID in
the projection, optionally with a Trigger


# Additional Changes

- none

# Additional Context

-  Allows reproduction of https://github.com/zitadel/zitadel/issues/8517

internal/query/debug_events.go

@@ -0,0 +1,106 @@
+package query
+
+import (
+	"context"
+	"database/sql"
+	_ "embed"
+	"errors"
+
+	"github.com/zitadel/zitadel/internal/api/authz"
+	"github.com/zitadel/zitadel/internal/domain"
+	"github.com/zitadel/zitadel/internal/eventstore/handler/v2"
+	"github.com/zitadel/zitadel/internal/query/projection"
+	"github.com/zitadel/zitadel/internal/telemetry/tracing"
+	"github.com/zitadel/zitadel/internal/zerrors"
+)
+
+type DebugEventState struct {
+	domain.ObjectDetails
+	Blob string
+}
+
+var (
+	//go:embed debug_events_state_by_id.sql
+	debugEventsStateByIdQuery string
+	//go:embed debug_events_states.sql
+	debugEventsStatesQuery string
+)
+
+func (q *Queries) GetDebugEventsStateByID(ctx context.Context, id string, triggerBulk bool) (_ *DebugEventState, err error) {
+	ctx, span := tracing.NewSpan(ctx)
+	defer func() { span.EndWithError(err) }()
+	ctx, err = triggerDebugEventsProjection(ctx, triggerBulk)
+	if err != nil {
+		return nil, err
+	}
+
+	dst := new(DebugEventState)
+	err = q.client.QueryRowContext(ctx,
+		func(row *sql.Row) error {
+			return row.Scan(
+				&dst.ID,
+				&dst.CreationDate,
+				&dst.EventDate,
+				&dst.ResourceOwner,
+				&dst.Sequence,
+				&dst.Blob,
+			)
+		},
+		debugEventsStateByIdQuery,
+		authz.GetInstance(ctx).InstanceID(),
+		id,
+	)
+	if errors.Is(err, sql.ErrNoRows) {
+		return nil, zerrors.ThrowNotFound(err, "QUERY-Eeth5", "debug event state not found")
+	}
+	if err != nil {
+		return nil, zerrors.ThrowInternal(err, "QUERY-oe0Ae", "Errors.Internal")
+	}
+	return dst, err
+}
+
+func (q *Queries) ListDebugEventsStates(ctx context.Context, triggerBulk bool) (out []DebugEventState, err error) {
+	ctx, span := tracing.NewSpan(ctx)
+	defer func() { span.EndWithError(err) }()
+	ctx, err = triggerDebugEventsProjection(ctx, triggerBulk)
+	if err != nil {
+		return nil, err
+	}
+
+	err = q.client.QueryContext(ctx,
+		func(rows *sql.Rows) error {
+			for rows.Next() {
+				var dst DebugEventState
+				err := rows.Scan(
+					&dst.ID,
+					&dst.CreationDate,
+					&dst.EventDate,
+					&dst.ResourceOwner,
+					&dst.Sequence,
+					&dst.Blob,
+				)
+				if err != nil {
+					return err
+				}
+				out = append(out, dst)
+			}
+			return rows.Err()
+		},
+		debugEventsStatesQuery,
+		authz.GetInstance(ctx).InstanceID(),
+	)
+
+	if err != nil {
+		return nil, zerrors.ThrowInternal(err, "QUERY-nooZ2", "Errors.Internal")
+	}
+	return out, nil
+}
+
+func triggerDebugEventsProjection(ctx context.Context, trigger bool) (_ context.Context, err error) {
+	if trigger {
+		ctx, span := tracing.NewSpan(ctx)
+		defer func() { span.EndWithError(err) }()
+		return projection.DebugEventsProjection.Trigger(ctx, handler.WithAwaitRunning())
+	}
+	return ctx, nil
+}