Toggle the pivot's grand-total row

The engine has no rollup mode that keeps subtotals and drops the grand
total, so the row is hidden in the grid's style listener instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ui/src/views/Forecast.jsx

@@ -180,6 +180,16 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
   useEffect(() => { localStorage.setItem('pf_scale_plug_v2', scalePlug) }, [scalePlug])
   useEffect(() => { localStorage.setItem('pf_panel_open', panelOpen ? 'open' : 'closed') }, [panelOpen])
 
+  // Whether the grand-total row is drawn. Per-browser, like the panel state: it
+  // is how you like to read the grid, not a property of the layout.
+  const [showTotalRow, setShowTotalRow] = useState(() => localStorage.getItem('pf_total_row') !== 'hidden')
+  const showTotalRowRef = useRef(showTotalRow)
+  useEffect(() => {
+    localStorage.setItem('pf_total_row', showTotalRow ? 'shown' : 'hidden')
+    showTotalRowRef.current = showTotalRow
+    gridRef.current?.regular_table?.draw()
+  }, [showTotalRow])
+
   // Esc closes the panel — the usual way out of the floating window
   useEffect(() => {
     if (!panelOpen) return
@@ -1219,11 +1229,27 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
       style.textContent = `
         td.pf-group-start { border-left: 2px solid currentColor; opacity: 1; }
         td.pf-subtotal    { font-weight: 600; background: color-mix(in srgb, currentColor 7%, transparent); }
+        tr.pf-total-row   { display: none; }
       `
       ;(root.head || root).appendChild(style)
     }
 
     table.addStyleListener(() => {
+      // The grand-total row, hidden on request. The engine has no rollup mode
+      // for "subtotals but no grand total" -- rollup, flat and total are the
+      // three -- so it is dropped here instead. It is view row 0 with a row
+      // header blank at every level; y alone is not enough, since under flat
+      // rollup there is no total and row 0 is a leaf. Tagged per draw, because
+      // the grid recycles its tr elements as it scrolls.
+      for (const tr of table.querySelectorAll('tbody tr')) {
+        const th = tr.querySelector('th')
+        let meta
+        try { meta = th ? table.getMeta(th) : null } catch { meta = null }
+        const isTotal = meta?.y === 0 && Array.isArray(meta.row_header) &&
+                        !meta.row_header.some(notBlank)
+        tr.classList.toggle('pf-total-row', isTotal && !showTotalRowRef.current)
+      }
+
       const body = table.querySelectorAll('tbody td')
       // The deepest column path is a leaf; anything shorter is an aggregate of
       // the levels below it, which is what makes a subtotal a subtotal.
@@ -2120,6 +2146,12 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
               <div className="pf-group-rule" />
               <DepthButtons label="Rows" levels={groupFull} depth={expandDepth}
                 onPick={applyDepth} totalLabel="Total" />
+              <label className="flex items-center gap-1 text-gray-600 cursor-pointer select-none"
+                title="Show the grand-total row at the top of the pivot">
+                <input type="checkbox" checked={showTotalRow}
+                  onChange={e => setShowTotalRow(e.target.checked)} />
+                Total row
+              </label>
             </>
           )}