Update room navigator skill with mock_interact and room verification

Replaces click-based navigation with mock_interact(0) on TransitionPiece
nodes, adds get_current_room_name() verification pattern, and documents
the MCP busy protocol for walk animation timeouts.

.opencode/plans/kq4-room-navigator.md

@@ -79,13 +79,14 @@ python tools/kq4_room_navigator.py --from kq4_004_ogres_cottage --to kq4_092_lol
 
 5. **Connect to MCP** (runtime): Opens TCP connection to port 9090
 6. **For each navigation step**:
-   a. `find_nodes_by_class(class_name="TransitionPiece")` — discover all transition pieces in current scene
-   b. Match the exit node name from our path → get runtime position + polygon
-   c. Compute click coordinate: centroid of the TransitionPiece's `polygon`, transformed to viewport coordinates
-   d. `click(x, y)` — trigger the transition
-   e. Wait for transition animation (2-3s via `wait` command or poll-loop)
-   f. **Verify**: `eval("return get_tree().root.get_node_or_null('Node2D/SceneViewport/background').name")` to confirm we've entered the expected room
-   g. If verification fails, retry up to 2 times with adjusted coordinates
+   a. Verify starting room: `eval("return get_node('/root/Node2D').get_current_room_name()")` returns the current room's node name (e.g., `"kq4_003_fountain_pool"`). This convenience function on MainGame simplifies verification compared to traversing the scene tree.
+   b. `find_nodes_by_class(class_name="TransitionPiece")` — discover all transition pieces in current scene
+   c. Match the exit node name from our path → get runtime position + polygon
+   d. Compute click coordinate: centroid of the TransitionPiece's `polygon`, transformed to viewport coordinates
+   e. `click(x, y)` — trigger the transition
+   f. Wait for transition animation (2-3s via `wait` command or poll-loop)
+   g. **Verify arrival**: `eval("return get_node('/root/Node2D').get_current_room_name()")` to confirm we've entered the expected room. Compare against the `to_room` from our BFS path. Returns empty string if no scene loaded.
+   h. If verification fails, retry up to 2 times with adjusted coordinates
    h. Optionally take a screenshot via `screenshot()` for visual confirmation
 
 7. **Complete**: Print summary of navigation path taken
@@ -118,12 +119,24 @@ The skill guide documents:
 - **When to use**: Planning navigation between rooms, verifying room connectivity, debugging transitions
 - **Pre-requisites**: Godot game running with MCP server active on port 9090
 - **Quick start**: `python tools/kq4_room_navigator.py --from kq4_XXX --to kq4_YYY`
+- **Room verification helper** (`MainGame.get_current_room_name()`):
+
+  The root node (`/root/Node2D`, script: `MainGame.gd`) provides a convenience function for testing:
+
+  ```gdscript
+  # Via MCP eval — returns node name like "kq4_003_fountain_pool", or "" if no scene loaded
+  return get_node("/root/Node2D").get_current_room_name()
+  ```
+
+  Use this after each transition click to verify you arrived at the expected room. Compare against the `to_room` field from your BFS path.
+
 - **Manual MCP workflow** (for step-by-step agent control):
   - Start Godot: `godot --path .` or run exported binary
+  - Check current room: `{"command": "eval", "params": {"code": "return get_node('/root/Node2D').get_current_room_name()"}}` → returns `"kq4_003_fountain_pool"` style string
   - Verify connectivity: `{"command": "get_scene_tree"}` returns the current scene tree
   - Discover exits in current room: `{"command": "find_nodes_by_class", "params": {"class_name": "TransitionPiece"}}`
   - Click a transition: compute centroid from polygon data, then `{"command": "click", "params": {"x": px, "y": py}}`
-  - Wait and verify room change via `eval` or `screenshot`
+  - Verify current room: `{"command": "eval", "params": {"code": "return get_node('/root/Node2D').get_current_room_name()"}}` (returns node name like `"kq4_010_forest_path"`). Alternatively use screenshot for visual confirmation.
 - **Coordinate computation math**: How to convert TransitionPiece polygon (local-space) to viewport click coordinates: `viewport_x = transition_node.position.x + polygon_centroid.x`, accounting for any node scale transforms
 - **Troubleshooting**: Common failures (server busy, node not found mid-transition, wrong room), escape hatches
 
@@ -134,6 +147,31 @@ The skill guide documents:
 ```
 [1. build_room_graph.py] ────────┐
                                  ├── [2. kq4_room_navigator.py] ─── [3. SKILL.md]
+
+### Using MainGame.get_current_room_name() for Room Verification
+
+The `MainGame.gd` script (attached to `/root/Node2D`) provides a convenience function:
+
+```gdscript
+# Returns the node name of the current scene, e.g., "kq4_003_fountain_pool"
+func get_current_room_name() -> String:
+	var scene = get_scene()
+	if scene:
+		return scene.name
+	return ""
+```
+
+**Via MCP eval for runtime verification**:
+```bash
+curl http://localhost:9090 -d '{"command": "eval", "params": {"code": "return get_node(\"/root/Node2D\").get_current_room_name()"}}'
+```
+
+Returns the room node name string (e.g., `"kq4_003_fountain_pool"`), or empty string if no scene is loaded. This is more reliable than traversing the scene tree manually since it uses the same `$SceneViewport/background` reference that MainGame's own logic uses.
+
+**When to use**:
+- After clicking a transition, call to confirm arrival at expected room in `to_room`
+- Before navigation starts, verify you're actually in the intended `from_room`
+- Compare against BFS path nodes during automated step-by-step execution
 ```
 
 Tasks run sequentially. Task 3 documents the completed system.