feat(net): nodes carry their cyberspace tile

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

crates/citygen/src/generate/net.rs

@@ -52,6 +52,7 @@ impl NetStage {
             id,
             kind,
             anchor,
+            cyber: anchor.1,
             subnet,
             building,
         });

crates/citygen/src/net.rs

@@ -66,6 +66,8 @@ pub struct Node {
     pub id: NodeId,
     pub kind: NodeKind,
     pub anchor: (StratumKind, Pos),
+    /// The node's tile on the Net stratum.
+    pub cyber: Pos,
     pub subnet: SubnetId,
     pub building: Option<BuildingId>,
 }
@@ -79,6 +81,11 @@ impl Net {
         self.nodes.iter().find(|n| n.anchor == (k, p))
     }
 
+    /// The node standing on a cyberspace tile.
+    pub fn node_in_cyber(&self, p: Pos) -> Option<&Node> {
+        self.nodes.iter().find(|n| n.cyber == p)
+    }
+
     pub fn subnet(&self, id: SubnetId) -> &Subnet {
         &self.subnets[id.index()]
     }
@@ -87,3 +94,32 @@ impl Net {
         &self.nodes[id.index()]
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn nodes_are_found_by_cyber_tile() {
+        let mut net = Net::default();
+        net.subnets.push(Subnet {
+            id: SubnetId(0),
+            owner: SubnetOwner::City,
+            security: 10,
+        });
+        net.nodes.push(Node {
+            id: NodeId(0),
+            kind: NodeKind::Server,
+            anchor: (StratumKind::Street, Pos::new(5, 5)),
+            cyber: Pos::new(7, 5),
+            subnet: SubnetId(0),
+            building: None,
+        });
+        assert_eq!(
+            net.node_in_cyber(Pos::new(7, 5)).map(|n| n.id),
+            Some(NodeId(0))
+        );
+        assert_eq!(net.node_in_cyber(Pos::new(5, 5)), None);
+        assert!(net.node_at(StratumKind::Street, Pos::new(5, 5)).is_some());
+    }
+}