(crawler) Add a migration workaround so we can still open old slop crawl data with the new column added

This is an interesting indicator of website quality.

code/processes/crawling-process/model/java/nu/marginalia/slop/SlopCrawlDataRecord.java

@@ -328,6 +328,7 @@ public record SlopCrawlDataRecord(String domain,
         private final LongColumn.Writer timestampColumnWriter;
         private final EnumColumn.Writer contentTypeColumnWriter;
         private final ByteArrayColumn.Writer bodyColumnWriter;
+        private final ShortColumn.Writer requestTimeColumnWriter;
         private final StringColumn.Writer headerColumnWriter;
 
         public Writer(Path path) throws IOException {
@@ -341,6 +342,7 @@ public record SlopCrawlDataRecord(String domain,
             timestampColumnWriter = timestampColumn.create(this);
             contentTypeColumnWriter = contentTypeColumn.create(this);
             bodyColumnWriter = bodyColumn.create(this);
+            requestTimeColumnWriter = requestTimeColumn.create(this);
             headerColumnWriter = headerColumn.create(this);
         }
 
@@ -353,6 +355,7 @@ public record SlopCrawlDataRecord(String domain,
             timestampColumnWriter.put(record.timestamp);
             contentTypeColumnWriter.put(record.contentType);
             bodyColumnWriter.put(record.body);
+            requestTimeColumnWriter.put((short) record.requestTimeMs);
             headerColumnWriter.put(record.headers);
         }
 
@@ -493,8 +496,18 @@ public record SlopCrawlDataRecord(String domain,
             timestampColumnReader = timestampColumn.open(this);
             contentTypeColumnReader = contentTypeColumn.open(this);
             bodyColumnReader = bodyColumn.open(this);
-            requestTimeColumnReader = requestTimeColumn.open(this);
             headerColumnReader = headerColumn.open(this);
+
+            // FIXME: After 2025-06-XX, we can remove this migration workaround
+            ShortColumn.Reader timeColumnReader;
+            try {
+                timeColumnReader = requestTimeColumn.open(this);
+            }
+            catch (Exception ex) {
+                // Migration workaround
+                timeColumnReader = null;
+            }
+            requestTimeColumnReader = timeColumnReader;
         }
 
         public SlopCrawlDataRecord get() throws IOException {
@@ -507,7 +520,7 @@ public record SlopCrawlDataRecord(String domain,
                     timestampColumnReader.get(),
                     contentTypeColumnReader.get(),
                     bodyColumnReader.get(),
-                    requestTimeColumnReader.get(),
+                    requestTimeColumnReader != null ? requestTimeColumnReader.get() : -1,
                     headerColumnReader.get()
             );
         }