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/schematic/schem/SchemLoader.java

@@ -12,18 +12,27 @@ import java.io.IOException;
 
 public final class SchemLoader {
 
+    private static final int MAX_FILE_SIZE = 10 * 1024 * 1024;
+
     private SchemLoader() {
     }
 
     @NotNull
     public static Clipboard load(@NotNull File file) throws IOException {
+        if (file.length() > MAX_FILE_SIZE) {
+            throw new IOException("Schematic file too large: " + file.getName());
+        }
         final ClipboardFormat format = ClipboardFormats.findByFile(file);
         if (format == null) {
             throw new IOException("Unsupported schematic file: " + file.getName());
         }
         try (FileInputStream in = new FileInputStream(file);
              ClipboardReader reader = format.getReader(in)) {
-            return reader.read();
+            final Clipboard clipboard = reader.read();
+            if (clipboard == null) {
+                throw new IOException("Schematic file returned no clipboard: " + file.getName());
+            }
+            return clipboard;
         }
     }
 }