Fix one-way travel, rework iris to SG-1 mechanics, glowstone chevrons, pin-locked shield

One-way travel bug: the exit point landed players directly inside the
destination gate's own iris footprint. Since dialing opens both ends,
arriving there immediately re-triggered the teleport listener and
bounced them straight back - reading exactly like one-way travel.
GateManager.computeSafeLanding now nudges the landing spot along the
player's travel direction until it clears the destination's iris
blocks, and GateTeleportListener adds a short per-player cooldown as a
second guard against re-trigger. Same-server teleports now also
preserve the player's exact yaw/pitch and velocity instead of forcing
a fixed stored orientation, so entering forward always means exiting
forward; the cross-server plugin-messaging protocol was extended to
carry yaw/pitch through the proxy hop for the same reason.

Iris rework to match SG-1 rather than a binary open/closed gate:
- Idle (not connected): iris-idle-material, default AIR - you see
  straight through an inactive ring, not a wall.
- Connected: iris-open-material (WATER, the event horizon) unless the
  gate's separate iris shield is closed, in which case
  iris-shield-material (IRON_BLOCK) blocks travel even though the
  wormhole is active.
- A button placed directly below the control sign toggles the shield
  (GateIrisButtonListener). Closing needs nothing; opening a gate with
  a pin code set (/sg pin <code>) prompts the player to type it in
  chat within gate.pin-timeout-seconds first.

Also: gate.chevron-lit-material default changed from gilded blackstone
to glowstone per feedback.

stargate-bungee/src/main/java/dev/skywalker3200/stargate/bungee/StargateBungeePlugin.java

@@ -22,7 +22,9 @@ import java.util.concurrent.ConcurrentHashMap;
 /** BungeeCord counterpart of the Velocity bridge: same wire protocol, same job. */
 public class StargateBungeePlugin extends Plugin implements Listener {
 
-    private final Map<UUID, String> pendingGateByPlayer = new ConcurrentHashMap<>();
+    private record PendingWarp(String gateId, float yaw, float pitch) {}
+
+    private final Map<UUID, PendingWarp> pendingGateByPlayer = new ConcurrentHashMap<>();
 
     @Override
     public void onEnable() {
@@ -44,6 +46,8 @@ public class StargateBungeePlugin extends Plugin implements Listener {
             UUID playerId = UUID.fromString(in.readUTF());
             String targetServer = in.readUTF();
             String gateId = in.readUTF();
+            float yaw = in.readFloat();
+            float pitch = in.readFloat();
 
             ProxiedPlayer player = ProxyServer.getInstance().getPlayer(playerId);
             ServerInfo target = ProxyServer.getInstance().getServerInfo(targetServer);
@@ -52,7 +56,7 @@ public class StargateBungeePlugin extends Plugin implements Listener {
                 return;
             }
 
-            pendingGateByPlayer.put(playerId, gateId);
+            pendingGateByPlayer.put(playerId, new PendingWarp(gateId, yaw, pitch));
             player.connect(target);
         } catch (Exception e) {
             getLogger().warning("Failed to process stargate plugin message: " + e.getMessage());
@@ -62,8 +66,8 @@ public class StargateBungeePlugin extends Plugin implements Listener {
     @EventHandler
     public void onServerConnected(ServerConnectedEvent event) {
         ProxiedPlayer player = event.getPlayer();
-        String gateId = pendingGateByPlayer.remove(player.getUniqueId());
-        if (gateId == null) return;
+        PendingWarp warp = pendingGateByPlayer.remove(player.getUniqueId());
+        if (warp == null) return;
 
         Server server = event.getServer();
         try {
@@ -71,7 +75,9 @@ public class StargateBungeePlugin extends Plugin implements Listener {
             DataOutputStream out = new DataOutputStream(bytes);
             out.writeByte(StargateChannel.OP_TELEPORT_DELIVER);
             out.writeUTF(player.getUniqueId().toString());
-            out.writeUTF(gateId);
+            out.writeUTF(warp.gateId());
+            out.writeFloat(warp.yaw());
+            out.writeFloat(warp.pitch());
             server.sendData(StargateChannel.CHANNEL, bytes.toByteArray());
         } catch (Exception e) {
             getLogger().warning("Failed to deliver stargate teleport: " + e.getMessage());