Replace CellTag with CellStructure and embed BaseBuilding

The refactor removes the `Buildings` enum and the `building` module,
replacing
`CellTag` with a new `CellStructure` enum that directly holds a
`BaseBuilding`.
A `get_owner` method is added to `BaseBuilding` to support the new
structure.
All related imports, constructors, and rendering logic are updated to
use
`CellStructure` instead of the old tag and building fields.

src/app/states/mod.rs

@@ -9,5 +9,5 @@ pub use main_menu::MainMenuState;
 pub use perk_decks::{PerkDecks, PerkDecksState};
 pub use settings::SettingsState;
 pub use skills_config::SkillsConfigState;
-pub use skirmish::{CellTag, GameMode, Players, SkirmishState, ZoomLevel};
+pub use skirmish::{CellStructure, GameMode, Players, SkirmishState, ZoomLevel};
 pub use skirmish_states::{FocusedCell, Offset};

src/app/states/skirmish.rs

@@ -1,4 +1,4 @@
-use crate::app::states::skirmish_states::BoardState;
+use crate::app::{buildings::BaseBuilding, states::skirmish_states::BoardState};
 use clap::ValueEnum;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -22,8 +22,8 @@ pub enum ZoomLevel {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum CellTag {
-    Base(Players),
+pub enum CellStructure {
+    Base(BaseBuilding),
     Tunel,
     Stone,
 }

src/app/states/skirmish_states/board.rs

@@ -1,7 +1,9 @@
 use crate::app::{
-    buildings::{BaseBuilding, Buildings},
+    buildings::BaseBuilding,
     helpers::{CellSizes, cell_size_helper, cells_area_helper},
-    states::{CellTag, FocusedCell, Offset, Players, ZoomLevel, skirmish_states::MoveFocusedCell},
+    states::{
+        CellStructure, FocusedCell, Offset, Players, ZoomLevel, skirmish_states::MoveFocusedCell,
+    },
     units::{MinerUnit, Units},
     widgets::CellWidget,
 };
@@ -62,12 +64,12 @@ impl BoardState {
                 let player_base: bool = row == player_base_coords.0 && col == player_base_coords.1;
                 let enemy_base: bool = row == enemy_base_coords.0 && col == enemy_base_coords.1;
 
-                let tag: CellTag = if player_base {
-                    CellTag::Base(Players::Player)
+                let structure: CellStructure = if player_base {
+                    CellStructure::Base(BaseBuilding::new(Players::Player))
                 } else if enemy_base {
-                    CellTag::Base(Players::Enemy)
+                    CellStructure::Base(BaseBuilding::new(Players::Enemy))
                 } else {
-                    CellTag::Stone
+                    CellStructure::Stone
                 };
 
                 let unit: Option<Units> = if player_base {
@@ -78,16 +80,8 @@ impl BoardState {
                     None
                 };
 
-                let building: Option<Buildings> = if player_base {
-                    Some(Buildings::Base(BaseBuilding::new(Players::Player)))
-                } else if enemy_base {
-                    Some(Buildings::Base(BaseBuilding::new(Players::Enemy)))
-                } else {
-                    None
-                };
-
                 rows.push(CellWidget::new(
-                    row, col, zoom_level, selected, tag, unit, building,
+                    row, col, zoom_level, selected, structure, unit,
                 ));
             }