feat: per-annotator validation support for multi-user overlap

- Validate API stores validations in per-annotator 'validations' array
- Each annotator's validation is independent; re-validating updates in-place
- AnnotationPanel shows only current user's validation status
- ProgressBar counts only current user's verified mentions
- Next-page prompt checks only current user's unverified mentions
- Tag edits (dataset_tag) still go at top level

app/api/validate/route.js

@@ -64,15 +64,43 @@ export async function PUT(request) {
             return NextResponse.json({ error: `Dataset index ${dataset_index} out of range` }, { status: 400 });
         }
 
-        // Merge updates into the dataset entry.
-        // Fields like dataset_tag go at top level.
-        // Fields like human_validated, human_verdict, annotator, validated_at go at top level.
-        // Only dataset_name sub-fields (text, confidence, etc.) go inside dataset_name.
+        // Per-annotator validation: store in a `validations` array.
+        // Each annotator gets their own entry; re-validating updates in-place.
         const currentEntry = pagesData[pageIdx].datasets[dataset_index];
-        pagesData[pageIdx].datasets[dataset_index] = {
-            ...currentEntry,
-            ...updates,
-        };
+        const annotator = updates.annotator || 'unknown';
+
+        // Separate validation fields from other updates (like dataset_tag edits)
+        const validationFields = ['human_validated', 'human_verdict', 'human_notes', 'annotator', 'validated_at'];
+        const isValidation = validationFields.some(f => f in updates);
+
+        if (isValidation) {
+            const validations = currentEntry.validations || [];
+            const existingIdx = validations.findIndex(v => v.annotator === annotator);
+            const validationEntry = {
+                human_validated: updates.human_validated,
+                human_verdict: updates.human_verdict,
+                human_notes: updates.human_notes || null,
+                annotator,
+                validated_at: updates.validated_at || new Date().toISOString(),
+            };
+
+            if (existingIdx >= 0) {
+                validations[existingIdx] = validationEntry;
+            } else {
+                validations.push(validationEntry);
+            }
+
+            pagesData[pageIdx].datasets[dataset_index] = {
+                ...currentEntry,
+                validations,
+            };
+        } else {
+            // Non-validation updates (e.g. dataset_tag edit) go at top level
+            pagesData[pageIdx].datasets[dataset_index] = {
+                ...currentEntry,
+                ...updates,
+            };
+        }
 
         // Save back
         if (isHFSpace()) {

app/components/AnnotationPanel.js

@@ -85,10 +85,13 @@ export default function AnnotationPanel({
                             const tag = ds.dataset_tag || 'named';
                             const style = TAG_STYLES[tag] || TAG_STYLES.named;
                             const isHuman = !!ds.annotator;
-                            const isValidated = ds.dataset_name?.human_validated;
-                            const humanVerdict = ds.dataset_name?.human_verdict;
-                            const humanNotes = ds.dataset_name?.human_notes;
-                            const validatedBy = ds.dataset_name?.annotator;
+
+                            // Per-annotator validation: look up current user's entry
+                            const myValidation = (ds.validations || []).find(v => v.annotator === annotatorName);
+                            const isValidated = myValidation?.human_validated === true;
+                            const humanVerdict = myValidation?.human_verdict;
+                            const humanNotes = myValidation?.human_notes;
+
                             const judgeVerdict = ds.dataset_name?.judge_verdict;
                             const judgeTag = ds.dataset_name?.judge_tag;
                             const isValidating = validatingIdx === i;
@@ -153,11 +156,11 @@ export default function AnnotationPanel({
                                         </span>
                                     )}
 
-                                    {/* Existing validation status */}
+                                    {/* Existing validation status (your own) */}
                                     {isValidated && (
                                         <div className={`validation-status ${humanVerdict ? 'correct' : 'wrong'}`}>
                                             {humanVerdict ? '✅ Validated correct' : '❌ Marked incorrect'}
-                                            <span className="validation-by"> by {validatedBy}</span>
+                                            <span className="validation-by"> by you</span>
                                             {humanNotes && (
                                                 <p className="validation-notes">Note: {humanNotes}</p>
                                             )}

app/components/ProgressBar.js

@@ -6,6 +6,7 @@ export default function ProgressBar({
     currentDoc,
     pageIdx,
     currentPageDatasets,
+    annotatorName,
 }) {
     if (!documents || documents.length === 0) return null;
 
@@ -17,9 +18,12 @@ export default function ProgressBar({
     const totalPages = currentDoc?.annotatable_pages?.length ?? 0;
     const currentPage = totalPages > 0 ? pageIdx + 1 : 0;
 
-    // 3. Mentions progress: verified vs total on current page
+    // 3. Mentions progress: verified by CURRENT USER vs total on current page
     const totalMentions = currentPageDatasets?.length ?? 0;
-    const verifiedMentions = currentPageDatasets?.filter(ds => ds.human_validated === true).length ?? 0;
+    const verifiedMentions = currentPageDatasets?.filter(ds => {
+        const myValidation = (ds.validations || []).find(v => v.annotator === annotatorName);
+        return myValidation?.human_validated === true;
+    }).length ?? 0;
 
     return (
         <div className="progress-container">

app/page.js

@@ -176,10 +176,13 @@ export default function Home() {
     };
 
     const handleNextPage = () => {
-        const unverified = currentPageDatasets.filter(ds => ds.human_validated !== true).length;
+        const unverified = currentPageDatasets.filter(ds => {
+            const myValidation = (ds.validations || []).find(v => v.annotator === annotatorName);
+            return myValidation?.human_validated !== true;
+        }).length;
         if (unverified > 0) {
             const proceed = confirm(
-                `⚠️ There are ${unverified} unverified data mention${unverified > 1 ? 's' : ''} on this page.\n\nDo you want to proceed to the next page?`
+                `⚠️ You have ${unverified} unverified data mention${unverified > 1 ? 's' : ''} on this page.\n\nDo you want to proceed to the next page?`
             );
             if (!proceed) return;
         }
@@ -435,6 +438,7 @@ export default function Home() {
                         currentDoc={currentDoc}
                         pageIdx={pageIdx}
                         currentPageDatasets={currentPageDatasets}
+                        annotatorName={annotatorName}
                     />
                     <div className="top-bar-user">
                         {annotatorName ? (