feat(examples): four runnable plugin examples

- player-load: load-on-join (PlayerReadyEvent → IO → modify).
- async-moderation: IAsyncEvent → coroutine bridge for chat moderation.
- periodic-leaderboard: pluginScope loop with parallel reads.
- bounty-board: kitchen-sink demo exercising every v0.1 primitive.

examples/async-moderation/README.md

@@ -0,0 +1,36 @@
+# async-moderation
+
+Listens to `PlayerChatEvent` (an `IAsyncEvent`), runs a fake 200ms moderation
+check off-thread, and on flagged messages bumps a `warnings` counter on the
+world thread + cancels the event so it never reaches other players.
+
+## What it shows
+
+- `eventRegistry.registerAsyncGlobal(PlayerChatEvent::class.java) { future -> … }` —
+  the global overload. `registerAsync` only matches `IAsyncEvent<Void>`, and
+  `PlayerChatEvent` isn't `Void`-keyed; the wrong overload compiles silently
+  and never fires.
+- `scope.future { … }` from `kotlinx-coroutines-jdk8` — bridges
+  `CompletableFuture` ↔ coroutines without `runBlocking`.
+- `withContext(AsyncDispatchers.HytaleIO) { … }` — for the simulated HTTP call.
+- Conditional `modify<T>(...)` + `event.isCancelled = true` — the canonical
+  shape for any moderation/filter handler.
+
+## Build
+
+```bash
+./gradlew shadowJar
+# → build/libs/async-moderation.jar
+```
+
+## Run
+
+1. Drop the JAR in `mods/`, wire `ModerationStatsBinding.componentType()` to
+   your registered component.
+2. Type a message containing `badword`, `spam`, or `scam` in chat.
+3. The message is suppressed; the sender's `ModerationStats.warnings`
+   increments on the world thread.
+
+The example uses a private `CoroutineScope` to make the supervisor
+relationship explicit. In a real plugin, `pluginScope(this)` is fine and
+flows through `Async.shutdown()` cleanly.