Add Miner stats and conditional audio flag

- Extend MinerUnit with hp, digging ability, and power, and provide
  getters for these fields.
- Update the Unit trait and Units enum to expose hp, max hp,
  can_dig, and digging_power, and enhance base_text to display them.
- Remove unnecessary `Eq` derives from several structs and enums.
- Introduce a `--disable-audio` CLI flag and conditionally spawn the
  audio thread based on its value.

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

@@ -3,7 +3,7 @@ use crate::app::states::skirmish_states::{
     units::{MinerUnit, Unit},
 };
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq)]
 pub enum Units {
     Miner(MinerUnit),
 }
@@ -28,9 +28,29 @@ impl Unit for Units {
     fn get_owner(&self) -> Players {
         self.unit().get_owner()
     }
+
+    fn get_hp(&self) -> u16 {
+        self.unit().get_hp()
+    }
+
+    fn get_max_hp(&self) -> u16 {
+        self.unit().get_max_hp()
+    }
+
+    fn get_can_dig(&self) -> bool {
+        self.unit().get_can_dig()
+    }
+
+    fn get_digging_power(&self) -> f32 {
+        self.unit().get_digging_power()
+    }
 }
 
 impl Unit for Option<Units> {
+    fn is_unit(&self) -> bool {
+        self.map_or(false, |u| u.is_unit())
+    }
+
     fn get_tag(&self) -> char {
         self.map_or(' ', |u| u.get_tag())
     }
@@ -43,7 +63,19 @@ impl Unit for Option<Units> {
         self.map_or(Players::Unclaimed, |u| u.get_owner())
     }
 
-    fn is_unit(&self) -> bool {
-        self.map_or(false, |u| u.is_unit())
+    fn get_hp(&self) -> u16 {
+        self.map_or(0, |u| u.get_hp())
+    }
+
+    fn get_max_hp(&self) -> u16 {
+        self.map_or(0, |u| u.get_max_hp())
+    }
+
+    fn get_can_dig(&self) -> bool {
+        self.map_or(false, |u| u.get_can_dig())
+    }
+
+    fn get_digging_power(&self) -> f32 {
+        self.map_or(0.0, |u| u.get_digging_power())
     }
 }