add logging and minor comments

Author: DavePearce

arithmetization/src/main/java/net/consensys/linea/plugins/rpc/tracegeneration/GenerateConflatedTracesV2.java

@@ -70,6 +70,11 @@ public GenerateConflatedTracesV2(
             endpointConfiguration.traceCompression());
     this.l1L2BridgeSharedConfiguration = lineaL1L2BridgeSharedConfiguration;
     this.traceFileCaching = endpointConfiguration.caching();
+    // log configuration
+    log.info("trace file caching {}", this.traceFileCaching ? "enabled." : "disabled.");
+    log.info(
+        "trace file compression {}",
+        endpointConfiguration.traceCompression() ? "enabled." : "disabled.");
   }
 
   public String getNamespace() {

arithmetization/src/main/java/net/consensys/linea/zktracer/LtTraceFile.java

@@ -78,11 +78,16 @@ public void write(long value) {
       }
     }
 
+    /**
+     * Write element bytes
+     *
+     * @param bytes stored in big-endian form and already trimmed.
+     */
     @Override
     public void write(byte[] bytes) {
       final int n = bitLengthOf(bytes);
       // Sanity check
-      if (n > bitWidth) {
+      if (n > bitWidth || bytes.length > byteWidth) {
         throw new IllegalArgumentException(name + " has invalid width (" + n + " bits)");
       }
       // Write padding (if necessary)