feat(onboarding): welcome eligible new players

src/main/java/games/dmg/leaf/LeafRuntime.java

@@ -2,6 +2,7 @@ package games.dmg.leaf;
 
 import java.io.IOException;
 import java.time.Instant;
+import java.time.temporal.ChronoUnit;
 import java.util.Objects;
 import java.util.UUID;
 import org.bukkit.Server;
@@ -51,6 +52,11 @@ public final class LeafRuntime {
         );
         stateManager.saveIfDirty();
         reconcile(player);
+        LeafSettings settings = settingsProvider.current();
+        Instant onboardingEnd = state.firstJoin().plus(settings.onboardingDays(), ChronoUnit.DAYS);
+        if (settings.enabled() && observedAt.isBefore(onboardingEnd)) {
+            player.sendMessage(LeafText.color(settings.welcomeMessage()));
+        }
         return state;
     }
 

src/test/java/games/dmg/leaf/LeafRuntimeTest.java

@@ -6,6 +6,7 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.ArgumentMatchers.contains;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -43,6 +44,49 @@ final class LeafRuntimeTest {
         verify(protection, org.mockito.Mockito.times(2)).apply(player, 1);
     }
 
+    @Test
+    void welcomesPlayersOnEachJoinOnlyDuringTheConfiguredWindow() throws Exception {
+        UUID playerId = UUID.randomUUID();
+        Player player = player(playerId, "Alex");
+        Server server = mock(Server.class);
+        when(server.getPlayer(playerId)).thenReturn(player);
+        LeafRuntime runtime = runtime(
+            server,
+            mock(LeafProtection.class),
+            temporaryDirectory.resolve("welcome.yml")
+        );
+        Instant firstJoin = Instant.parse("2026-08-01T00:00:00Z");
+
+        runtime.observe(player, firstJoin);
+        runtime.observe(player, firstJoin.plusSeconds(6 * 86_400L));
+        runtime.observe(player, firstJoin.plusSeconds(7 * 86_400L));
+
+        verify(player, times(2)).sendMessage(contains("/leaf on, /leaf off, or /leaf status"));
+        verify(player, times(2)).sendMessage(contains("Attacking another player opts you out"));
+        assertEquals(firstJoin, runtime.status(playerId).firstJoin());
+    }
+
+    @Test
+    void suppressesWelcomeWhileLeafIsGloballyDisabled() throws Exception {
+        UUID playerId = UUID.randomUUID();
+        Player player = player(playerId, "Alex");
+        Server server = mock(Server.class);
+        when(server.getPlayer(playerId)).thenReturn(player);
+        LeafRuntime runtime = new LeafRuntime(
+            server,
+            new LeafSettingsProvider(LeafSettings.from(Map.of("enabled", false))),
+            new LeafStateManager(new YamlLeafStateRepository(
+                temporaryDirectory.resolve("disabled-welcome.yml")
+            )),
+            mock(LeafProtection.class),
+            mock(LeafIdentity.class)
+        );
+
+        runtime.observe(player, Instant.parse("2026-08-01T00:00:00Z"));
+
+        verify(player, never()).sendMessage(contains("Leaf protection is available"));
+    }
+
     @Test
     void lockedPlayerCannotChangeTheirChoice() throws Exception {
         UUID playerId = UUID.randomUUID();