fix: show panic output when fullscreen app panic

[hsqStephenZhang]

What It Does

setup panic handler before enter fullscreen mode
in the handler, leave current screen before printing the backtrace, so that panic output own't get lost along with that screen

Related Issues

#103

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.92%. Comparing base (4c8bf90) to head (c55a637).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #114   +/-   ##
=======================================
  Coverage   87.92%   87.92%           
=======================================
  Files          35       35           
  Lines        5617     5617           
  Branches     5617     5617           
=======================================
  Hits         4939     4939           
  Misses        569      569           
  Partials      109      109           

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[ccbrown]

Thanks for the PR! I like the idea, but I don't love exposing crossterm and requiring users to use it directly. If the stack is allowed to unwind, fullscreen will be exited normally, so I wonder if something like this would be better:

diff --git a/examples/fullscreen.rs b/examples/fullscreen.rs
index 41d4424..ebf87fb 100644
--- a/examples/fullscreen.rs
+++ b/examples/fullscreen.rs
@@ -1,6 +1,10 @@
 use chrono::Local;
 use iocraft::prelude::*;
-use std::time::Duration;
+use std::{backtrace::Backtrace, cell::Cell, time::Duration};
+
+thread_local! {
+    static BACKTRACE: Cell<Option<Backtrace>> = const { Cell::new(None) };
+}
 
 #[component]
 fn Example(mut hooks: Hooks) -> impl Into<AnyElement<'static>> {
@@ -21,6 +25,7 @@ fn Example(mut hooks: Hooks) -> impl Into<AnyElement<'static>> {
             TerminalEvent::Key(KeyEvent { code, kind, .. }) if kind != KeyEventKind::Release => {
                 match code {
                     KeyCode::Char('q') => should_exit.set(true),
+                    KeyCode::Char('p') => panic!("oh no!"),
                     _ => {}
                 }
             }
@@ -54,11 +59,23 @@ fn Example(mut hooks: Hooks) -> impl Into<AnyElement<'static>> {
             ) {
                 Text(content: format!("Current Time: {}", time.get().format("%r")))
             }
-            Text(content: "Press \"q\" to quit.")
+            Text(content: "Press \"q\" to quit or \"p\" to panic.")
         }
     }
 }
 
 fn main() {
-    smol::block_on(element!(Example).fullscreen()).unwrap();
+    std::panic::set_hook(Box::new(|_| {
+        let trace = Backtrace::capture();
+        BACKTRACE.with(move |b| b.set(Some(trace)));
+    }));
+
+    if std::panic::catch_unwind(|| {
+        smol::block_on(element!(Example).fullscreen()).unwrap();
+    })
+    .is_err()
+    {
+        let b = BACKTRACE.with(|b| b.take()).unwrap();
+        println!("panic:\n\n{b}");
+    }
 }

[hsqStephenZhang]

yeah agreed, catching and print the panic explictly info a better approach without exposing crossterm