feat: Add growth_stage to TileState

tests/interaction.rs

@@ -179,6 +179,7 @@ fn test_water_crop() {
             TileState::Occupied {
                 seed: seed_type.clone(),
                 watered: false,
+                growth_stage: 0,
             },
         )],
         vec![],

tests/pathfinding.rs

@@ -94,6 +94,7 @@ fn test_find_path_around_obstacle() {
             name: "Test".into(),
         },
         watered: false,
+        growth_stage: 0,
     };
     let obstacles = vec![
         (2, 2, obstacle.clone()),
@@ -146,6 +147,7 @@ fn test_find_path_no_path() {
             name: "Test".into(),
         },
         watered: false,
+        growth_stage: 0,
     };
     let obstacles = vec![
         (2, 0, obstacle.clone()),