feat(world): Haunted Manor content expansion (14 rooms, one world)

Replace the 5-room demo with a condensed 14-room manor on one spine
(restore power -> escape) that stacks all five mechanics, plus an optional
spirit thread feeding 3 prioritized endings (no hard-fail). Pure YAML on the
existing engines: 14 rooms across 3 levels, ~16 items, 5 combinations, the
old_man hint NPC, restore_power + lay_to_rest quests, and 3 endings.

Consolidate to one world: remove the toy "Test Manor" test fixture so the
loader tests exercise the real shipped world. Adapt WorldLoaderTest and
TutorialLoaderTest to form-invariants of the real world, and add
WorldSolvableTest, which walks the critical path (light/lock gating +
Combinations.tryUse + flags) to guarantee power_on, ghost_banished, and a
victory ending are reachable — an unsolvable world now fails the build.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/src/main/resources/world/rooms.yaml

@@ -1,64 +1,199 @@
+# Haunted Manor — 14 rooms across three levels, wired over compass exits.
+# Ground floor (manor-theme), cellar (cellar-drone, dark), upper floor
+# (musicbox / lament). The upward stair is power-locked; everything else is open.
+
+# ── Ground floor ──────────────────────────────────────────────────────────
+
+- id: foyer
+  name: Entrance Foyer
+  description: |
+    A grand, decaying foyer. The heavy front door stands at your back; an
+    oil lamp waits on a side table. A wide archway opens north into the hall.
+  music: manor-theme.ogg
+  exits:
+    north: grand_hall
+  items: [front_door, lamp]
+  npcs: []
+
+- id: grand_hall
+  name: Grand Hall
+  description: |
+    A cavernous hall, the hub of the house. Passages branch in every
+    direction: the foyer to the south, a dining room north, the kitchen
+    east, and the library west.
+  music: manor-theme.ogg
+  exits:
+    south: foyer
+    north: dining_room
+    east: kitchen
+    west: library
+  items: []
+  npcs: []
+
 - id: kitchen
   name: Old Kitchen
   description: |
-    A dusty kitchen. Cobwebs hang from the rafters
-    and a letter lies on the table.
+    A dusty kitchen. Cobwebs hang from the rafters, a box of matches sits
+    by the stove, and a letter lies on the table. A narrow stair descends
+    south into darkness.
   music: manor-theme.ogg
   exits:
-    north: hallway
-    east: cellar
-    south: dungeon
-  items: [letter, lamp, front_door]
-  npcs: [old_man]
-  exitLocks:
-    - direction: east
-      requires: [{ flag: power_on }]
-      blocked: |
-        The cellar door is held shut by a magnetic lock — dead without power.
-
-- id: hallway
-  name: Dark Hallway
-  description: |
-    A long, dimly lit hallway. It smells musty.
-    Faint footsteps echo somewhere far away.
-  exits:
-    south: kitchen
-    west: library
-  items: [torch]
+    west: grand_hall
+    south: cellar_stairs
+  items: [matches, letter]
   npcs: []
 
 - id: library
   name: Library
   description: |
-    Tall shelves crammed with mouldering books.
-    An old chest stands in the corner.
+    Tall shelves crammed with mouldering books. A rusty shovel leans in one
+    corner and a leather journal lies open on a reading stand. A stooped old
+    man keeps watch among the stacks.
+  music: manor-theme.ogg
   exits:
-    east: hallway
-  items: [shovel, matches]
+    east: grand_hall
+  items: [shovel, journal]
+  npcs: [old_man]
+
+- id: dining_room
+  name: Dining Room
+  description: |
+    A long banquet table under a sheet of dust. An unlit torch rests in a
+    wall bracket and a faded portrait hangs above the hearth. A conservatory
+    lies north; a grand staircase rises to the east.
+  music: manor-theme.ogg
+  exits:
+    south: grand_hall
+    north: conservatory
+    east: grand_staircase
+  items: [torch, portrait]
   npcs: []
 
-- id: cellar
-  name: Damp Cellar
+- id: conservatory
+  name: Conservatory
   description: |
-    Cold, damp, and very dark. You can barely
-    make out shapes against the far wall.
+    A glass-roofed room choked with dead ferns. Rusted plumbing lines the
+    walls, and a heavy iron valve wheel has been left on a potting bench.
+  music: manor-theme.ogg
   exits:
-    west: kitchen
+    south: dining_room
+  items: [valve_wheel]
+  npcs: []
+
+- id: grand_staircase
+  name: Grand Staircase
+  description: |
+    A sweeping staircase climbs into the gloom of the upper floor. The dining
+    room lies west. Without power, the lift gate at the top is sealed shut.
+  music: manor-theme.ogg
+  exits:
+    west: dining_room
+    north: landing
   items: []
   npcs: []
-  descriptionStates:
-    - when: [{ flag: power_on }]
-      text: |
-        With the power back, a bare bulb buzzes overhead, revealing
-        shelves of dusty jars along the far wall.
+  exitLocks:
+    - direction: north
+      requires: [{ flag: power_on }]
+      blocked: |
+        The lift gate at the head of the stairs is bolted by a dead electric
+        lock. Until the manor has power, the upper floor stays out of reach.
 
-- id: dungeon
-  name: Dungeon
+# ── Cellar (dark — needs a carried light source) ────────────────────────────
+
+- id: cellar_stairs
+  name: Cellar Landing
   description: |
-    A cramped stone room, black as pitch. A rusty generator squats in the corner.
-  music: dungeon-drone.ogg
+    The bottom of the kitchen stair. The air is wet and close. Passages lead
+    east toward the sound of standing water and west toward a cold furnace.
+  music: cellar-drone.ogg
   dark: true
   exits:
     north: kitchen
+    east: flooded_cellar
+    west: boiler_room
+  items: []
+  npcs: []
+
+- id: flooded_cellar
+  name: Flooded Cellar
+  description: |
+    You stand knee-deep in black, freezing water. A drainage valve juts from
+    the wall, its wheel long since removed.
+  music: cellar-drone.ogg
+  dark: true
+  exits:
+    west: cellar_stairs
+  items: [valve]
+  npcs: []
+  descriptionStates:
+    - when: [{ flag: cellar_drained }]
+      text: |
+        The drained basin has given up its muddy floor. The valve still
+        stands open against the wall, water trickling away below.
+
+- id: boiler_room
+  name: Boiler Room
+  description: |
+    A cramped stone room behind the furnace. A rusty generator squats in the
+    corner, an empty fuse socket gaping in its housing.
+  music: cellar-drone.ogg
+  dark: true
+  exits:
+    east: cellar_stairs
   items: [generator]
   npcs: []
+
+# ── Upper floor (reachable only once the power is on) ───────────────────────
+
+- id: landing
+  name: Upper Landing
+  description: |
+    A railed landing above the hall, lit now by the restored lights. Doors
+    open north to the master bedroom, east to a study, and west to a small
+    chapel. The staircase falls away to the south.
+  music: musicbox.ogg
+  exits:
+    south: grand_staircase
+    north: master_bedroom
+    east: study
+    west: chapel
+  items: []
+  npcs: []
+
+- id: master_bedroom
+  name: Master Bedroom
+  description: |
+    A grand four-poster bed, its drapes rotted to lace. On the nightstand,
+    catching the light, lies a silver locket.
+  music: musicbox.ogg
+  exits:
+    south: landing
+  items: [locket]
+  npcs: []
+
+- id: study
+  name: Study
+  description: |
+    A cluttered writing study. Papers lie scattered across the desk, and a
+    framed photograph has fallen face-up among them.
+  music: musicbox.ogg
+  exits:
+    west: landing
+  items: [photograph]
+  npcs: []
+
+- id: chapel
+  name: Manor Chapel
+  description: |
+    A tiny private chapel. A stone shrine stands at the far end beneath a
+    narrow window. A cold presence presses against you here.
+  music: lament.ogg
+  exits:
+    east: landing
+  items: [shrine]
+  npcs: []
+  descriptionStates:
+    - when: [{ flag: ghost_banished }]
+      text: |
+        A tiny private chapel. The shrine stands quiet beneath the window,
+        and only still moonlight remains. The cold presence is gone.