CI: add rust/ build+test workflow

data/dungeons/mangar_1.json

@@ -0,0 +1,31 @@
+{
+  "id": "mangar_1",
+  "name": "Mangar's Tower - Level 1",
+  "dungeon": "mangar",
+  "level": 1,
+  "width": 22,
+  "height": 22,
+  "description": "The ground floor of Mangar's Tower. The evil archmage's fortress is defended by magical constructs and traps at every turn.",
+  "encounter_level": 5,
+  "special_squares": [
+    { "x": 0, "y": 0, "type": "stairs_up", "destination": "skara_brae", "label": "Return to Skara Brae" },
+    { "x": 1, "y": 0, "type": "teleport_in", "destination": "kylearan_1", "label": "Arrived from Kylearan's Tower" },
+    { "x": 21, "y": 21, "type": "stairs_down", "destination": "mangar_2", "label": "Descend to Mangar's Tower Level 2" },
+    { "x": 11, "y": 5, "type": "special_encounter", "text": "The Maze Master! A cunning creature that warps the dungeon layout!", "encounter": "maze_master" },
+    { "x": 7, "y": 3, "type": "trap", "text": "Mangar's magical traps! Arcane flames engulf the corridor!", "damage": "3d6" },
+    { "x": 15, "y": 4, "type": "anti_magic", "text": "Mangar's anti-magic wards are potent here. No spells can be cast." },
+    { "x": 4, "y": 8, "type": "darkness", "text": "Magical darkness. Mangar does not want visitors to see his defenses." },
+    { "x": 17, "y": 9, "type": "spinner", "text": "Mangar's maze spell twists the corridors. You are thoroughly lost." },
+    { "x": 9, "y": 12, "type": "silence", "text": "Mangar's silence spell. Even the air feels dead." },
+    { "x": 14, "y": 14, "type": "special_encounter", "text": "A Soul Sucker! It feeds on your life force!", "encounter": "soul_sucker" },
+    { "x": 6, "y": 16, "type": "trap", "text": "A teleportation trap sends you hurtling through space! You arrive disoriented.", "damage": "1d8" },
+    { "x": 19, "y": 15, "type": "message", "text": "Mangar's propaganda: 'All who enter my tower shall serve me in death.'" },
+    { "x": 3, "y": 19, "type": "darkness", "text": "The walls pulse with a sickly green light that hurts your eyes." },
+    { "x": 12, "y": 18, "type": "spinner", "text": "A revolving room. The exits keep changing position." },
+    { "x": 20, "y": 8, "type": "message", "text": "A barracks for Mangar's summoned creatures. Currently empty." }
+  ],
+  "connections": [
+    { "from_x": 21, "from_y": 21, "to": "mangar_2", "type": "stairs_down" },
+    { "from_x": 0, "from_y": 0, "to": "skara_brae", "type": "stairs_up" }
+  ]
+}