Attributes: static registry ids, not format! per mob and tick

The type's default of an attribute (base_value, read by mob movement and
every tick's entity tracking) and the LAN attribute sync built the id
"minecraft:<name>" with format! on each call: for a server's 2000 mobs that
is several allocations per mob per tick. Attr::id returns the id as a
static string.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

crates/horizon-client/src/game/lan_attributes.rs

@@ -121,15 +121,12 @@ impl Game<'_> {
         }
         if let Some(s) = m.extra.attributes.as_deref() {
             for (attr, v) in &s.bases {
-                if let Some(a) = self.synced_attribute(kind, &format!("minecraft:{}", attr.name()))
-                {
+                if let Some(a) = self.synced_attribute(kind, attr.id()) {
                     instance(out, a, *v).base = *v;
                 }
             }
             for x in &s.modifiers {
-                if let Some(a) =
-                    self.synced_attribute(kind, &format!("minecraft:{}", x.attr.name()))
-                {
+                if let Some(a) = self.synced_attribute(kind, x.attr.id()) {
                     add_modifier(
                         out,
                         a,

crates/horizon-client/src/mobs/finalize.rs

@@ -435,6 +435,21 @@ impl Attr {
             Self::BurningTime => "burning_time",
         }
     }
+    /// The attribute's registry id (`minecraft:` and its name), without
+    /// building it: mob ticks and entity tracking ask for every mob.
+    pub fn id(self) -> &'static str {
+        match self {
+            Self::MaxHealth => "minecraft:max_health",
+            Self::MovementSpeed => "minecraft:movement_speed",
+            Self::FollowRange => "minecraft:follow_range",
+            Self::AttackDamage => "minecraft:attack_damage",
+            Self::KnockbackResistance => "minecraft:knockback_resistance",
+            Self::SpawnReinforcements => "minecraft:spawn_reinforcements",
+            Self::JumpStrength => "minecraft:jump_strength",
+            Self::Armor => "minecraft:armor",
+            Self::BurningTime => "minecraft:burning_time",
+        }
+    }
     /// `RangedAttribute` bounds.
     fn range(self) -> (f64, f64) {
         match self {
@@ -473,10 +488,7 @@ pub struct Attributes {
 }
 /// The type's default value of an attribute, if the mob has it.
 pub fn default_value(m: &Mob, a: Attr) -> Option<f64> {
-    m.kind
-        .attributes
-        .get(&format!("minecraft:{}", a.name()))
-        .copied()
+    m.kind.attributes.get(a.id()).copied()
 }
 pub fn base_value(m: &Mob, a: Attr) -> f64 {
     m.extra