Add ore level support and unify text rendering

Introduce a numeric `level` field for `BaseBuilding` and `Ore`, update
their
constructors and `get_level` implementations, and increase the default
ore
amount to the new maximum. Extend the `Structure` and `Unit` traits with
`base_text` and `text` methods, add `is_unit` to `Units`, and adjust the
`Structures` enum to delegate text rendering. Refactor `SidePanelWidget`
to
use the unified trait methods, removing duplicated rendering code.
Update
`BoardState` to create ore structures with an initial level of 1.

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

@@ -42,4 +42,8 @@ impl Unit for Option<Units> {
     fn get_owner(&self) -> Players {
         self.map_or(Players::Unclaimed, |u| u.get_owner())
     }
+
+    fn is_unit(&self) -> bool {
+        self.map_or(false, |u| u.is_unit())
+    }
 }

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

@@ -1,7 +1,27 @@
 use crate::app::states::skirmish_states::Players;
+use ratatui::{
+    style::Stylize,
+    text::{Line, Span},
+};
 
 pub trait Unit {
     fn get_owner(&self) -> Players;
+
     fn get_tag(&self) -> char;
+
     fn get_name(&self) -> &'static str;
+
+    fn is_unit(&self) -> bool {
+        true
+    }
+
+    fn base_text(&self) -> Vec<Line<'_>> {
+        let owner: Span<'_> = self.get_owner().get_span();
+
+        vec![Line::from_iter(vec!["Owner: ".gray(), owner])]
+    }
+
+    fn text(&self) -> Vec<Line<'_>> {
+        self.base_text()
+    }
 }