fix: resolve 11 P1 bugs from audit (leaderboard, SQL, coop, jump, lifecycle, schematics, config)

- leaderboard: parse M:SS.mmm/H:MM:SS(.mmm), switch TIME sort to long (п.25)
- sql: single Hikari pool, non-blocking connect, adaptive init order, settings JSON round-trip (п.27-30)
- coop: remove unregister recursion via session-only leave + reentrancy guard (п.24)
- jump: perpendicular jitter for diagonal heading, valid safety-fallback on retry exhaustion (п.32-33)
- lifecycle: fall threshold relative to course, lead via generated-blocks counter, one-time rewards once (п.35-37)
- schematics: catch RuntimeExceptions, validate size, 10MB file limit (п.31)
- config merge: preserve block-sequence lists and ignored sections, fix path reversal (п.26)
- tests: +31 (score, jump, schematics, config merge) = 72 total

src/main/java/dev/loki/loparkour/player/service/UserRegistry.java

@@ -61,23 +61,32 @@ public final class UserRegistry {
     }
 
     public static void unregister(@NotNull ParkourUser user, boolean restorePreviousData, boolean kickIfBungee, boolean urgent) {
-        dev.loki.loparkour.adaptive.bootstrap.AdaptiveServices.unloadPlayer(user.getUUID());
-        new ParkourLeaveEvent(user).call();
-
-        try {
-            user.unregister();
-            resetScoreboard(user);
-        } catch (Exception ex) {
-            handleUnregisterError(user, ex);
-        }
-
-        if (restorePreviousData && shouldKickToBungee(kickIfBungee)) {
-            BungeeUtil.sendPlayerToServer(user.player, Config.CONFIG.getString("bungeecord.return_server"));
+        if (user.unregistering) {
             return;
         }
 
-        if (restorePreviousData) {
-            restorePreviousState(user, urgent);
+        user.unregistering = true;
+        try {
+            dev.loki.loparkour.adaptive.bootstrap.AdaptiveServices.unloadPlayer(user.getUUID());
+            new ParkourLeaveEvent(user).call();
+
+            try {
+                user.unregister();
+                resetScoreboard(user);
+            } catch (Exception ex) {
+                handleUnregisterError(user, ex);
+            }
+
+            if (restorePreviousData && shouldKickToBungee(kickIfBungee)) {
+                BungeeUtil.sendPlayerToServer(user.player, Config.CONFIG.getString("bungeecord.return_server"));
+                return;
+            }
+
+            if (restorePreviousData) {
+                restorePreviousState(user, urgent);
+            }
+        } finally {
+            user.unregistering = false;
         }
     }