Lock variant and prompt edits while judge is running

Both fields now disable on isLocked (streaming OR judging) instead of
just isStreaming, matching the gating already applied to the Run button
and header inputs. Also gate the JudgeCard on !isStreaming so a stale
verdict from the previous run doesn't render alongside a new in-flight
stream.

Author: slaFFik

src/web/components/VariantColumn.tsx

@@ -209,13 +209,13 @@ export function VariantColumn(props: {
 
       <VariantEditor
         value={column.variantContent}
-        disabled={isStreaming}
+        disabled={isLocked}
         onChange={(v) => void props.onPatchColumn(column.id, { variantContent: v })}
       />
 
       <PromptField
         value={column.prompt}
-        disabled={isStreaming}
+        disabled={isLocked}
         onChange={(v) => void props.onPatchColumn(column.id, { prompt: v })}
       />
 
@@ -270,11 +270,12 @@ export function VariantColumn(props: {
         </div>
       )}
 
-      {runBundle?.judge ? (
-        <JudgeCard judge={runBundle.judge} />
-      ) : isJudging ? (
-        <JudgeCard judging />
-      ) : null}
+      {!isStreaming &&
+        (runBundle?.judge ? (
+          <JudgeCard judge={runBundle.judge} />
+        ) : isJudging ? (
+          <JudgeCard judging />
+        ) : null)}
     </div>
   );
 }