[eric] desktop: sidebar toggle pins the sidebar open in fullscreen; card anchors to the viewport so docked chrome squeezes it

frontend/src/app/components/Layout/AppShell.tsx

@@ -444,7 +444,10 @@ const AppShell: React.FC = () => {
   // Zen compact mode: the sidebar is the only chrome now, so whenever it's "away" (user collapsed it,
   // OR a fullscreen card hides everything) a left-edge hover floats it back in as an overlay.
   const fsActive = !!fullscreenCardId && isDashboardViewActive;
-  const sidebarAway = (sidebarCollapsed || fsActive) && isDashboardViewActive;
+  // Arc: the sidebar toggle PINS the sidebar open inside fullscreen (docked, card shrinks beside it);
+  // unpinned fullscreen keeps the hover-peek overlay.
+  const [fsSidebarPinned, setFsSidebarPinned] = useState(false);
+  const sidebarAway = (sidebarCollapsed || (fsActive && !fsSidebarPinned)) && isDashboardViewActive;
   const [sidePeek, setSidePeek] = useState(false);
   useEffect(() => { if (!sidebarAway) setSidePeek(false); }, [sidebarAway]);
   // When the sidebar docks away, the canvas runs flush to the window's left edge, so the floating
@@ -849,7 +852,7 @@ const AppShell: React.FC = () => {
       )}
 
       <Box sx={{ display: 'flex', flex: 1, minHeight: 0 }}>
-      {((!sidebarCollapsed && !fsHideChrome) || sideOverlay) && (
+      {((!sidebarCollapsed && (!fsHideChrome || fsSidebarPinned)) || sideOverlay) && (
       <>
       <Box
         onMouseEnter={() => { if (sideOverlay) cancelPeekClose(); }}
@@ -900,7 +903,16 @@ const AppShell: React.FC = () => {
             <Tooltip title={sideOverlay ? 'Dock sidebar' : 'Hide sidebar'}>
               {/* Arc-style pin: from the floating peek this DOCKS the sidebar permanently (pushes the
                   canvas), from docked it collapses back to peek. Toggle, not one-way collapse. */}
-              <IconButton size="small" onClick={() => setSidebarCollapsed((v) => !v)}
+              <IconButton size="small" onClick={() => {
+                  if (fsActive) {
+                    setFsSidebarPinned((v) => {
+                      if (!v) setSidebarCollapsed(false);
+                      return !v;
+                    });
+                    return;
+                  }
+                  setSidebarCollapsed((v) => !v);
+                }}
                 data-onboarding="sidebar-toggle" aria-expanded={!sidebarCollapsed}
                 sx={{ color: c.text.tertiary, p: 0.5, borderRadius: 1, '&:hover': { color: c.text.secondary, bgcolor: `${c.text.tertiary}14` } }}>
                 <AnimatedPanelLeft size={17} />

frontend/src/app/pages/Dashboard/cards/tileZones.ts

@@ -48,19 +48,17 @@ function workspaceSize(): { w: number; h: number } {
 }
 
 export function computeTiledStyle(zone: string, panX: number, panY: number, zoom: number): TiledStyle | null {
-  // 'fullscreen' = the Arc layout: the app chrome hides except the dock rail, which stays put on
-  // the left, and the card expands into the ENTIRE dashboard beside it, floating on the same gap
-  // the tile zones use. Target is WINDOW space here, so the viewport origin does NOT cancel.
+  // 'fullscreen' = the Arc layout: the dock rail stays put on the left and the card expands into
+  // the ENTIRE dashboard beside it, floating on the same gap the tile zones use. Anchored to the
+  // VIEWPORT (not the window) so docked chrome, like the pinned sidebar, squeezes the card instead
+  // of being covered by it.
   if (zone === 'fullscreen') {
-    const el = document.querySelector('[data-canvas-viewport]');
-    const r = el ? el.getBoundingClientRect() : null;
-    const ox = r ? r.left : 0;
-    const oy = r ? r.top : 0;
+    const { w: vpW, h: vpH } = workspaceSize();
     return {
-      left: (FULLSCREEN_DOCK_RAIL + GAP - ox - panX) / zoom,
-      top: (GAP - oy - panY) / zoom,
-      width: window.innerWidth - FULLSCREEN_DOCK_RAIL - GAP * 2,
-      height: window.innerHeight - GAP * 2,
+      left: (FULLSCREEN_DOCK_RAIL + GAP - panX) / zoom,
+      top: (GAP - panY) / zoom,
+      width: vpW - FULLSCREEN_DOCK_RAIL - GAP * 2,
+      height: vpH - GAP * 2,
       transform: `scale(${1 / zoom})`,
       transformOrigin: 'top left',
     };