fix(simulation): clippy — erasing_op row-major literals, range-contains in T-1116 tests

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

server/src/atlas/road_graph.rs

@@ -2146,13 +2146,13 @@ mod tests {
         let grid = RouteGrid::build(&ta, &[], w, h);
         assert_eq!(grid.scale, 3, "grid_w=180 must downsample at scale=3 for ROUTE_W=64");
 
-        let majority_water_cell = 0 * grid.rw + 3;
+        let majority_water_cell = 3; // row-major (row 0, col 3)
         assert_eq!(
             grid.cost[majority_water_cell],
             IMPASSABLE,
             "2-of-3 native cells water (a true majority) must be IMPASSABLE"
         );
-        let minority_water_cell = 0 * grid.rw + 6;
+        let minority_water_cell = 6; // row-major (row 0, col 6)
         assert_ne!(
             grid.cost[minority_water_cell],
             IMPASSABLE,
@@ -2174,7 +2174,7 @@ mod tests {
             (0, 3),
             "the surrogate must NOT be the impassable cell itself"
         );
-        assert!(ring >= 1 && ring <= COASTAL_ANCHOR_MAX_RING);
+        assert!((1..=COASTAL_ANCHOR_MAX_RING).contains(&ring));
     }
 
     /// T-1116 boundary case: a settlement placement fully surrounded by