Keep muzzle flashes and attached effects playing past the first minutes

spawn_effect takes one of 255 bolt records for every effect played on a
tag, and nothing gave them back: run_garbage_collection cleared the
effect slot and dropped the record. A minute or two into a match with
bots, the muzzle flashes and shell ejects of every shot had used them
all, and from then on every bolted effect failed with EffectLimit and was
dropped without a word. That took later muzzle flashes, the jets'
afterburners and the precision airstrike's cluster bomb, which is played
on its tag_origin model and spawns the bomblets' ground explosions, so
the airstrike did its damage with no fire or smoke.

Garbage collection now puts a dead effect's record back on the free
list, and the ring-full check runs before a record is taken, so that
refusal no longer leaks one either.

Seen on an iPhone build on mp_terminal before the fix: Uzi muzzle flashes
at 0:30, none under steady fire at 2:40, and no fire or smoke where a
precision airstrike landed about 3 minutes in. With the fix, in another
match on the same map, the stealth bomber's fire and smoke showed and the
player's SCAR still flashed 4 minutes in.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/fx/src/system.rs

@@ -860,6 +860,14 @@ impl FxSystemHost {
         Some(idx as u8)
     }
 
+    fn free_bolt_record(&mut self, index: u8) {
+        let Some(next) = self.bolt_next.get_mut(usize::from(index)) else {
+            return;
+        };
+        *next = self.bolt_first_free;
+        self.bolt_first_free = i32::from(index);
+    }
+
     pub fn spawn_effect(
         &mut self,
         def_name: &str,
@@ -873,6 +881,9 @@ impl FxSystemHost {
         if wants_spotlight && self.spotlight_count >= FX_SPOT_LIGHT_LIMIT {
             return Err(SpawnFail::TooManySpotlights);
         }
+        if self.ring_occupancy() >= FX_EFFECT_HANDLE_RING_SIZE as i32 {
+            return Err(SpawnFail::RingFull);
+        }
         let bolt_index = if bolt == FX_SPAWN_BOLT_NONE {
             0xff
         } else {
@@ -883,9 +894,6 @@ impl FxSystemHost {
         };
 
         let alloc = self.first_free_effect;
-        if self.ring_occupancy() >= FX_EFFECT_HANDLE_RING_SIZE as i32 {
-            return Err(SpawnFail::RingFull);
-        }
         self.first_free_effect = alloc.wrapping_add(1);
 
         let ring_i = (alloc as u32 & (FX_EFFECT_HANDLE_RING_SIZE - 1)) as usize;
@@ -986,6 +994,10 @@ impl FxSystemHost {
             self.set_handle_at_ring(active_index as u32, handle);
             active_index = active_index.wrapping_add(1);
             if let Some(slot) = handle_to_slot(handle) {
+                let bolt = self.effects[slot].bolt;
+                if bolt != 0xff {
+                    self.free_bolt_record(bolt);
+                }
                 self.effects[slot] = FxEffectSlot::default();
             }
         }