Add tests, fix offset logic, and bump dependencies

- Introduce a comprehensive test suite (cli, app, board, tasks, audio)
  and a
  new TESTING.md document describing test execution.
- Correct vertical offset calculation in `BoardState` to use saturating
  subtraction and ceiling division.
- Clamp initial `Offset` values to the provided maximum in
  `Offset::new`.
- Export `load_audio` from the audio thread module and switch to
  `LoopedDecoder` for proper OGG looping.
- Update several crate versions: clap, ratatui, log, rodio, and
  bitflags.

tests/tasks.rs

@@ -0,0 +1,50 @@
+use war_in_tunnels::app::states::skirmish_states::{
+    Players,
+    tasks::{DiggingTask, Task, Tasks},
+    units::{MinerUnit, Unit},
+};
+
+#[test]
+fn digging_progress_accumulates_and_stops_at_completion() {
+    let mut task = DiggingTask::new([(5, 3)].into(), 40.0);
+    assert!(!task.is_finished());
+    task.progress();
+    assert_eq!(task.get_progress(), 40.0);
+    assert!(!task.is_finished());
+    for _ in 0..3 {
+        task.progress();
+    }
+    assert_eq!(task.get_progress(), 100.0);
+    assert!(task.is_finished());
+}
+
+#[test]
+fn advancing_path_resets_progress_and_handles_empty_path() {
+    let mut task = DiggingTask::new([(5, 3), (5, 4)].into(), 25.0);
+    task.progress();
+    task.pop_front();
+    assert_eq!(task.current_target(), Some((5, 4)));
+    assert_eq!(task.get_progress(), 0.0);
+    task.pop_front();
+    task.pop_front();
+    assert_eq!(task.current_target(), None);
+    assert!(task.get_path().is_empty());
+}
+
+#[test]
+fn miners_keep_tasks_in_submission_order() {
+    let mut miner = MinerUnit::new(Players::Player, (5, 2));
+    for target in [(5, 3), (6, 3)] {
+        miner.set_task(Tasks::Digging(DiggingTask::new([target].into(), 1.0)));
+    }
+    assert_eq!(miner.get_ref_tasks().len(), 2);
+    assert_eq!(
+        *miner
+            .get_mut_tasks()
+            .pop_front()
+            .unwrap()
+            .get_path_front_coords(),
+        (5, 3)
+    );
+    assert_eq!(*miner.get_ref_tasks()[0].get_path_front_coords(), (6, 3));
+}