fix: task slicing index range restraints

index.html

@@ -379,7 +379,7 @@ $.set('#subcategory', 'change', (e) => {
 });
 
 $.set('#chunksize', 'change', (e) => {
-    let limit = Math.max(minor, major - 1);
+    let limit = Math.max(minor || major - 1, 0);
     let value = Math.floor(limit / e.target.valueAsNumber);
     $('#limit').value = value;
     $('#offset').max = value;
@@ -448,11 +448,11 @@ while (await new Promise(o => setTimeout(o, 1000, true))) {
             $('#send').classList.add('pulse');
             $('#timezoneLabel').innerText = Temporal.Now.zonedDateTimeISO(locale.timezone).toLocaleString(locale.name);
 
-            let { done, skip, omit, email, subject, recipient } = await Rpc2.invoke('progress').catch(() => new Object());
-            let limit = minor || major - 1;
+            let { done, skip, email, subject, recipient } = await Rpc2.invoke('progress').catch(() => new Object());
+            let count = done + skip;
+            let limit = Math.max(minor || major - 1, 0);
             let chunk = $('#chunksize').valueAsNumber;
             let total = $('#slice').checked ? Math.min(chunk, limit - chunk * $('#offset').valueAsNumber) : limit;
-            let count = $('#slice').checked ? done + skip - omit : done + skip;
 
             $('#progressLabel').innerText = `${parseFloat(count / total * 100).toFixed(2)}% (${count}/${total})`;
             $('#subjectLabel').innerText = subject ?? '';