fix(tables): only add real row positions in shift-click range select

Previously the loop added every integer from..to, which in sparse
tables (with deleted rows) could add thousands of phantom gap positions.
Now iterates positionMap to only add positions with actual rows.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/tables/[tableId]/components/table/table.tsx

@@ -539,10 +539,11 @@ export function Table({
     if (shiftKey && lastCheckboxRowRef.current !== null) {
       const from = Math.min(lastCheckboxRowRef.current, rowIndex)
       const to = Math.max(lastCheckboxRowRef.current, rowIndex)
+      const pMap = positionMapRef.current
       setCheckedRows((prev) => {
         const next = new Set(prev)
-        for (let i = from; i <= to; i++) {
-          next.add(i)
+        for (const [pos] of pMap) {
+          if (pos >= from && pos <= to) next.add(pos)
         }
         return next
       })