feat: seed Aschenratte and Straßenräuber for Verbrannte Straße

Adds the two starter monster definitions and their location-monster
mapping (weights 70/30) to the vertical-slice seed, following the
same findOneBy/update-or-insert pattern used for locations, plus an
upsert on (locationId, monsterId) for the mapping. Copies the source
artwork into the served images/monsters directory and extends the
seed spec harness to cover both idempotent inserts.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

apps/api/src/database/seeds/vertical-slice.seed.ts

@@ -1,9 +1,17 @@
 import { DataSource } from 'typeorm';
 import { DEMO_CHARACTER_ID } from '../../demo/demo-character.constants';
 import { Character } from '../../characters/entities/character.entity';
+import { EncounterType } from '../../monsters/entities/encounter-type.enum';
+import { LocationMonster } from '../../monsters/entities/location-monster.entity';
+import { MonsterDefinition } from '../../monsters/entities/monster-definition.entity';
 import { LocationConnection } from '../../world/entities/location-connection.entity';
 import { LocationDefinition } from '../../world/entities/location-definition.entity';
-import { BURNED_ROAD_ID, SOUTH_GATE_ID } from './vertical-slice.constants';
+import {
+  ASH_RAT_MONSTER_ID,
+  BURNED_ROAD_ID,
+  ROAD_BANDIT_MONSTER_ID,
+  SOUTH_GATE_ID,
+} from './vertical-slice.constants';
 
 export async function seedVisibleVerticalSlice(
   dataSource: DataSource,
@@ -11,6 +19,9 @@ export async function seedVisibleVerticalSlice(
   const locationRepository = dataSource.getRepository(LocationDefinition);
   const connectionRepository = dataSource.getRepository(LocationConnection);
   const characterRepository = dataSource.getRepository(Character);
+  const monsterRepository = dataSource.getRepository(MonsterDefinition);
+  const locationMonsterRepository =
+    dataSource.getRepository(LocationMonster);
 
   const locations = [
     {
@@ -85,6 +96,77 @@ export async function seedVisibleVerticalSlice(
     ['fromLocationId', 'toLocationId'],
   );
 
+  const monsters = [
+    {
+      id: ASH_RAT_MONSTER_ID,
+      key: 'ash-rat',
+      name: 'Aschenratte',
+      level: 1,
+      maxHp: 45,
+      attack: 5,
+      armor: 0,
+      experienceReward: 8,
+      silverMin: 4,
+      silverMax: 7,
+      artworkPath: '/images/monsters/ash-rat.png',
+    },
+    {
+      id: ROAD_BANDIT_MONSTER_ID,
+      key: 'road-bandit',
+      name: 'Straßenräuber',
+      level: 2,
+      maxHp: 75,
+      attack: 9,
+      armor: 5,
+      experienceReward: 16,
+      silverMin: 9,
+      silverMax: 15,
+      artworkPath: '/images/monsters/road-bandit.png',
+    },
+  ];
+  let ashRatId = ASH_RAT_MONSTER_ID;
+  let roadBanditId = ROAD_BANDIT_MONSTER_ID;
+
+  for (const monster of monsters) {
+    const existingMonster = await monsterRepository.findOneBy({
+      key: monster.key,
+    });
+    const { id, key, ...definition } = monster;
+    const persistedId = existingMonster?.id ?? id;
+
+    if (existingMonster) {
+      await monsterRepository.update(existingMonster.id, definition);
+    } else {
+      await monsterRepository.insert(monster);
+    }
+
+    if (key === 'ash-rat') {
+      ashRatId = persistedId;
+    } else {
+      roadBanditId = persistedId;
+    }
+  }
+
+  await locationMonsterRepository.upsert(
+    [
+      {
+        locationId: burnedRoadId,
+        monsterId: ashRatId,
+        weight: 70,
+        encounterType: EncounterType.NORMAL,
+        enabled: true,
+      },
+      {
+        locationId: burnedRoadId,
+        monsterId: roadBanditId,
+        weight: 30,
+        encounterType: EncounterType.NORMAL,
+        enabled: true,
+      },
+    ],
+    ['locationId', 'monsterId'],
+  );
+
   const existing = await characterRepository.findOneBy({
     id: DEMO_CHARACTER_ID,
   });