fix log entries that don't have a playthrough_id

```
select * from deaths order by log_id desc limit 1;
+--------+---------+---------+--------------+------------+----------+----------+--------+------+
| log_id | name | killer | killerclass | damagetype | x | y | z | id |
+--------+---------+---------+--------------+------------+----------+----------+--------+------+
| 489819 | jesus11 | jesus11 | JCDentonMale | exploded | -1822.81 | -113.169 | -219.2 | 7592 |
+--------+---------+---------+--------------+------------+----------+----------+--------+------+
```

```
select * from logs where id=489819;
+------------------+---------------------+----------+----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+------------+--------+---------+-----------+----------------+
| map | created | version | ip | message | seed | flagshash | id | modname | firstword | playthrough_id |
+------------------+---------------------+----------+----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+------------+--------+---------+-----------+----------------+
| 15_Area51_bunker | 2023-02-12 03:48:11 | v2.2.4.5 | 203.217.93.123 | EVENT: 15_Area51_bunker.JCDentonMale10: {"type":"DEATH","victim":"jesus11","victimBindName":"JCDenton","victimRandomizedName":"","killerclass":"JCDentonMale","killer":"jesus11","killerRandomizedName":"","dmgtype":"exploded","PlayerName":"jesus11","map":"15_AREA51_BUNKER","mapname":"Area 51 - Bunker","mission":"15","TrueNorth":"0","PlayerIsFemale":"False","GameMode":"Normal Randomizer","newgameplus_loops":"0","loadout":"All Items Allowed","location":"-1822.809814,-113.168938,-219.199997"}
| 713664 | 1801441664 | 489819 | DeusEx | NULL | 630850919 |
+------------------+---------------------+----------+----------------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+------------+--------+---------+-----------+----------------+
```

it's janky code... maybe we should fix it on the unrealscript side

Start by tracing how deaths and logs are created and how playthrough_id is assigned, using the shown records as a reproduction. Check the UnrealScript side mentioned in the issue and verify that affected log entries consistently receive a playthrough_id without breaking existing records.

Written by the indexing model from the issue text.