Move buildings and units under skirmish_states

Reorganize the codebase by moving the buildings and units modules
into the skirmish_states namespace, updating imports accordingly.

src/app/states/skirmish_states/board.rs

@@ -1,11 +1,9 @@
 use crate::app::{
-    buildings::BaseBuilding,
     helpers::{CellSizes, cell_size_helper, cells_area_helper},
     states::{
         CellStructure, FocusedCell, Offset, Players, Units, ZoomLevel,
-        skirmish_states::MoveFocusedCell,
+        skirmish_states::{MoveFocusedCell, buildings::BaseBuilding, units::MinerUnit},
     },
-    units::MinerUnit,
     widgets::CellWidget,
 };
 use ratatui::layout::Rect;

src/app/states/skirmish_states/buildings/base.rs

@@ -0,0 +1,35 @@
+use crate::app::states::Players;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct BaseBuilding {
+    owner: Players,
+    level: u8,
+    tag: &'static str,
+}
+
+impl BaseBuilding {
+    pub fn new(owner: Players) -> Self {
+        Self {
+            owner,
+            level: 1,
+            tag: "B",
+        }
+    }
+
+    pub fn get_owner(&self) -> Players {
+        self.owner
+    }
+
+    pub fn get_tag(&self) -> &'static str {
+        self.tag
+    }
+
+    pub fn get_level(&self) -> &'static str {
+        match self.level {
+            1 => "1",
+            2 => "2",
+            3 => "3",
+            _ => " ",
+        }
+    }
+}

src/app/states/skirmish_states/buildings/mod.rs

@@ -0,0 +1,3 @@
+mod base;
+
+pub use base::BaseBuilding;

src/app/states/skirmish_states/mod.rs

@@ -1,6 +1,8 @@
 mod board;
+pub mod buildings;
 mod focused_cell;
 mod offset;
+pub mod units;
 
 pub use board::BoardState;
 pub use focused_cell::{FocusedCell, MoveFocusedCell};

src/app/states/skirmish_states/units/miner.rs

@@ -0,0 +1,17 @@
+use crate::app::states::Players;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct MinerUnit {
+    owner: Players,
+    tag: &'static str,
+}
+
+impl MinerUnit {
+    pub fn new(owner: Players) -> Self {
+        Self { owner, tag: "M" }
+    }
+
+    pub fn get_tag(self) -> &'static str {
+        self.tag
+    }
+}

src/app/states/skirmish_states/units/mod.rs

@@ -0,0 +1,3 @@
+mod miner;
+
+pub use miner::MinerUnit;