refactor(command): simplify region lookup in GravityFlip commands

- Replaced manual region search loops with a new `find` method in RegionRegistry for improved readability and efficiency.
- Updated `GravityFlipToggleSubCommand` and `GravityFlipTpSubCommand` to utilize the new method for finding regions by name.
- Enhanced the `add` method in RegionRegistry to use the `find` method for checking existing region names.

src/main/java/com/mythlane/gravityflip/command/GravityFlipToggleSubCommand.java

@@ -27,13 +27,7 @@ public final class GravityFlipToggleSubCommand extends CommandBase {
     @Override
     protected void executeSync(@Nonnull CommandContext ctx) {
         String name = nameArg.get(ctx);
-        GravityFlipRegion found = null;
-        for (GravityFlipRegion r : plugin.regions().all()) {
-            if (r.getName().equals(name)) {
-                found = r;
-                break;
-            }
-        }
+        GravityFlipRegion found = plugin.regions().find(name);
         if (found == null) {
             ctx.sendMessage(Message.raw("[gravityflip] Region '" + name + "' not found."));
             return;

src/main/java/com/mythlane/gravityflip/command/GravityFlipTpSubCommand.java

@@ -40,13 +40,7 @@ public final class GravityFlipTpSubCommand extends AbstractPlayerCommand {
                            @Nonnull PlayerRef playerRef,
                            @Nonnull World world) {
         String name = nameArg.get(ctx);
-        GravityFlipRegion target = null;
-        for (GravityFlipRegion r : plugin.regions().all()) {
-            if (r.getName().equals(name)) {
-                target = r;
-                break;
-            }
-        }
+        GravityFlipRegion target = plugin.regions().find(name);
         if (target == null) {
             ctx.sendMessage(Message.raw("[gravityflip] Region '" + name + "' not found."));
             return;

src/main/java/com/mythlane/gravityflip/region/RegionRegistry.java

@@ -78,13 +78,20 @@ public final class RegionRegistry {
         return out;
     }
 
+    /** Returns the region with the given name from the current snapshot, or null. */
+    public GravityFlipRegion find(String name) {
+        if (name == null) return null;
+        for (GravityFlipRegion x : regionsSnapshot.get()) {
+            if (x.getName().equals(name)) return x;
+        }
+        return null;
+    }
+
     /** Adds a region; throws IllegalArgumentException if the name already exists. */
     public void add(GravityFlipRegion r) {
         synchronized (mutationLock) {
-            for (GravityFlipRegion x : regionsSnapshot.get()) {
-                if (x.getName().equals(r.getName())) {
-                    throw new IllegalArgumentException("region name already exists: " + r.getName());
-                }
+            if (find(r.getName()) != null) {
+                throw new IllegalArgumentException("region name already exists: " + r.getName());
             }
             config.getRegions().add(r);
             regionsSnapshot.set(List.copyOf(config.getRegions()));

src/main/java/com/mythlane/gravityflip/tick/RegionTickLoop.java

@@ -65,11 +65,10 @@ public final class RegionTickLoop {
             World w = worldSupplier.get();
             if (w == null) return;
             registry.refreshFor(w);
-            if (gravityApplier != null) {
-                gravityApplier.apply(w, registry.currentSnapshot(w));
-            }
-            if (regionVisualizer != null) {
-                regionVisualizer.visualize(w, registry.currentSnapshot(w));
+            if (gravityApplier != null || regionVisualizer != null) {
+                var snapshot = registry.currentSnapshot(w);
+                if (gravityApplier != null) gravityApplier.apply(w, snapshot);
+                if (regionVisualizer != null) regionVisualizer.visualize(w, snapshot);
             }
         };
         scheduleGuarded(initialDelayMs, tick);