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 91.58%. Comparing base (79d852a) to head (47066be).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #114   +/-   ##
=======================================
  Coverage   91.58%   91.58%           
=======================================
  Files          29       29           
  Lines        4715     4715           
  Branches     4715     4715           
=======================================
  Hits         4318     4318           
  Misses        309      309           
  Partials       88       88           

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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