CI: add rust/ build+test workflow

data/dungeons/catacombs_2.json

@@ -0,0 +1,30 @@
+{
+  "id": "catacombs_2",
+  "name": "Catacombs - Level 2",
+  "dungeon": "catacombs",
+  "level": 2,
+  "width": 22,
+  "height": 22,
+  "description": "The middle catacombs. The dead here are more powerful and the architecture grows more ancient. Strange rituals were performed in these halls.",
+  "encounter_level": 3,
+  "special_squares": [
+    { "x": 0, "y": 0, "type": "stairs_up", "destination": "catacombs_1", "label": "Return to Catacombs Level 1" },
+    { "x": 21, "y": 21, "type": "stairs_down", "destination": "catacombs_3", "label": "Descend to Catacombs Level 3" },
+    { "x": 7, "y": 3, "type": "special_encounter", "text": "A zombie lord commands a shambling horde!", "encounter": "zombie_lord" },
+    { "x": 14, "y": 5, "type": "trap", "text": "A curse tablet crumbles under your boot. Dark magic latches onto you!", "damage": "1d8" },
+    { "x": 4, "y": 7, "type": "darkness", "text": "The darkness here seems to have weight. It presses against you." },
+    { "x": 10, "y": 9, "type": "anti_magic", "text": "Runes carved into the floor form a magic-suppression circle." },
+    { "x": 17, "y": 11, "type": "spinner", "text": "The catacomb maze disorients you completely." },
+    { "x": 3, "y": 13, "type": "silence", "text": "An enchanted silence zone. The dead sleep silently here." },
+    { "x": 19, "y": 15, "type": "message", "text": "A ritual chamber. Dark stains on the altar suggest blood sacrifice." },
+    { "x": 8, "y": 17, "type": "trap", "text": "A ceiling collapse! Dust and rubble rain down!", "damage": "2d6" },
+    { "x": 13, "y": 19, "type": "special_encounter", "text": "Wraiths drift through the walls, surrounding you!", "encounter": "wraith_circle" },
+    { "x": 20, "y": 3, "type": "message", "text": "A sealed vault. The lock requires a special key to open." },
+    { "x": 6, "y": 10, "type": "spinner", "text": "You enter a circular chamber with six identical exits." },
+    { "x": 16, "y": 18, "type": "darkness", "text": "Even magical light fizzles in this area." }
+  ],
+  "connections": [
+    { "from_x": 21, "from_y": 21, "to": "catacombs_3", "type": "stairs_down" },
+    { "from_x": 0, "from_y": 0, "to": "catacombs_1", "type": "stairs_up" }
+  ]
+}