Effect panels: borrow the name and reuse the icon key

The panel list is painted every frame the inventory is open. An unclipped
name was cloned per panel and the icon key was a fresh format! per panel; the
name is borrowed and the key is built in one buffer now.

Co-Authored-By: Hermes Agent (Nous Research) <[email protected]>

crates/horizon-client/src/inventory_effects.rs

@@ -1,5 +1,7 @@
 //! `EffectsInInventory`: active effect panels beside survival and creative
 //! inventories, with compact icons when there is little room on the right.
+use std::borrow::Cow;
+
 use crate::{
     effects::EffectInstance,
     hud::{HudAtlas, HudBatch},
@@ -123,17 +125,19 @@ pub fn paint(
     cursor: [i32; 2],
 ) -> Option<[(String, u32); 2]> {
     let mut tooltip = None;
+    let mut icon = String::new();
     for panel in panels {
         background(batch, atlas, panel);
         let text_width = panel.width - 39;
         let clipped = atlas.font.width(&panel.name).ceil() as i32 > text_width;
         if text_width > 0 {
-            let shown = if clipped {
+            let shown: Cow<'_, str> = if clipped {
                 let available = text_width as f32 - atlas.font.width("...");
                 let count = atlas.font.fit(&panel.name, available);
-                format!("{}...", panel.name.chars().take(count).collect::<String>())
+                let text: String = panel.name.chars().take(count).collect();
+                Cow::Owned(format!("{text}..."))
             } else {
-                panel.name.clone()
+                Cow::Borrowed(panel.name.as_str())
             };
             batch.text(
                 atlas,
@@ -152,9 +156,12 @@ pub fn paint(
                 true,
             );
         }
+        icon.clear();
+        icon.push_str("mob_effect/");
+        icon.push_str(&panel.icon.id);
         batch.sprite_scaled(
             atlas,
-            &format!("mob_effect/{}", panel.icon.id),
+            &icon,
             (panel.x + 7) as f32,
             (panel.y + 7) as f32,
             18.0,