fix: reduce TUI idle CPU and improve server error banners

- Replace non-blocking try_recv() event loop with blocking recv() to
  eliminate idle spin; the sender tick timeout still drives minimum
  wakeup rate so the UI stays responsive
- Lower default tick rate from 50 ms to 100 ms (10 ticks/sec vs 20);
  add MANAGARR_TICK_RATE_MS env var for runtime tuning
- Move terminal draws to event boundaries (key + tick) instead of every
  loop pass, reducing unnecessary redraws
- In network error handling, prefer concise JSON fields (message /
  errorMessage / error) over the raw HTTP body, so Radarr ASP.NET
  stack traces don't flood the TUI banner; full body still logged
- Add unit tests for tick-rate parsing and Radarr-style JSON error body

Observed: ~0.6% total CPU at idle vs measurably higher with prod defaults

src/event/input_event.rs

@@ -1,4 +1,5 @@
 use anyhow::Result;
+use std::env;
 use std::sync::mpsc;
 use std::sync::mpsc::Receiver;
 use std::thread;
@@ -18,10 +19,24 @@ pub struct Events {
   rx: Receiver<InputEvent<Key>>,
 }
 
+const DEFAULT_TICK_RATE_MS: u64 = 100;
+
+fn configured_tick_rate_ms_from(raw: Option<&str>) -> u64 {
+  raw
+    .and_then(|value| value.parse::<u64>().ok())
+    .filter(|ms| *ms > 0)
+    .unwrap_or(DEFAULT_TICK_RATE_MS)
+}
+
+fn configured_tick_rate_ms() -> u64 {
+  let raw = env::var("MANAGARR_TICK_RATE_MS").ok();
+  configured_tick_rate_ms_from(raw.as_deref())
+}
+
 impl Events {
   pub fn new() -> Self {
     let (tx, rx) = mpsc::channel();
-    let tick_rate: Duration = Duration::from_millis(50);
+    let tick_rate: Duration = Duration::from_millis(configured_tick_rate_ms());
 
     thread::spawn(move || {
       let mut last_tick = Instant::now();
@@ -51,9 +66,33 @@ impl Events {
   }
 
   pub fn next(&self) -> Result<Option<InputEvent<Key>>> {
-    match self.rx.try_recv() {
+    match self.rx.recv() {
       Ok(event) => Ok(Some(event)),
       _ => Ok(None),
     }
   }
 }
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn defaults_to_a_slower_idle_tick_rate() {
+    assert_eq!(DEFAULT_TICK_RATE_MS, 100);
+    assert_eq!(configured_tick_rate_ms_from(None), 100);
+  }
+
+  #[test]
+  fn parses_positive_tick_rates_and_rejects_invalid_values() {
+    assert_eq!(configured_tick_rate_ms_from(Some("250")), 250);
+    assert_eq!(
+      configured_tick_rate_ms_from(Some("0")),
+      DEFAULT_TICK_RATE_MS
+    );
+    assert_eq!(
+      configured_tick_rate_ms_from(Some("abc")),
+      DEFAULT_TICK_RATE_MS
+    );
+  }
+}