CI: add rust/ build+test workflow

data/dungeons/harkyn_2.json

@@ -0,0 +1,30 @@
+{
+  "id": "harkyn_2",
+  "name": "Harkyn's Castle - Level 2",
+  "dungeon": "harkyn",
+  "level": 2,
+  "width": 22,
+  "height": 22,
+  "description": "The middle levels of Harkyn's Castle. The architecture grows more twisted and nightmarish. Harkyn's dark experiments are evident.",
+  "encounter_level": 4,
+  "special_squares": [
+    { "x": 0, "y": 0, "type": "stairs_up", "destination": "harkyn_1", "label": "Return to Harkyn's Level 1" },
+    { "x": 21, "y": 21, "type": "stairs_down", "destination": "harkyn_3", "label": "Descend to Harkyn's Level 3" },
+    { "x": 10, "y": 4, "type": "special_encounter", "text": "One of Harkyn's failed experiments lurches toward you!", "encounter": "harkyn_experiment" },
+    { "x": 5, "y": 7, "type": "trap", "text": "Alchemical reagents on a shelf explode when disturbed!", "damage": "2d6" },
+    { "x": 15, "y": 6, "type": "anti_magic", "text": "Harkyn's laboratory equipment creates an anti-magic field." },
+    { "x": 3, "y": 11, "type": "darkness", "text": "No light penetrates the dungeon cells. You hear moaning from within." },
+    { "x": 17, "y": 9, "type": "spinner", "text": "A rotating wall segment confuses your sense of direction." },
+    { "x": 8, "y": 14, "type": "silence", "text": "Soundproofed torture chambers. A profound, unnatural silence." },
+    { "x": 13, "y": 16, "type": "message", "text": "Notes in Harkyn's hand: 'The Mad God must be freed to reach Mangar.'" },
+    { "x": 19, "y": 13, "type": "trap", "text": "A magical trap! Lightning arcs from the walls!", "damage": "2d8" },
+    { "x": 6, "y": 18, "type": "special_encounter", "text": "A bone golem guards Harkyn's inner sanctum!", "encounter": "bone_golem" },
+    { "x": 20, "y": 18, "type": "message", "text": "A teleportation circle - inactive but humming with residual energy." },
+    { "x": 11, "y": 10, "type": "trap", "text": "A pit trap lined with spikes!", "damage": "2d6" },
+    { "x": 4, "y": 4, "type": "darkness", "text": "The walls are covered in scratch marks - made by human fingernails." }
+  ],
+  "connections": [
+    { "from_x": 21, "from_y": 21, "to": "harkyn_3", "type": "stairs_down" },
+    { "from_x": 0, "from_y": 0, "to": "harkyn_1", "type": "stairs_up" }
+  ]
+}