feat(base): use negative margin to extend inline grid past parent

The previous approach (position: relative + explicit width +
inset-inline-start) didn't physically grow the box in some flex
contexts, so the grid stayed at the parent's width. Switch to
negative margin-left / margin-right on the grid wrapper only —
with width: auto, the rendered width becomes parent + |margin|,
extending the box past the parent without any positioning hacks.

The toolbar keeps its natural parent-constrained width (no extension)
so it stays aligned with the page text above. Two CSS vars,
--embed-extend-l / --embed-extend-r, are computed on mount + on
ResizeObserver from the wrapper and the closest wider ancestor.

apps/client/src/features/base/components/base-table.tsx

@@ -314,27 +314,16 @@ export function BaseTable({ pageId, embedded }: BaseTableProps) {
 
   if (!base) return null;
 
-  // When the table is embedded inline in a doc page, the parent
-  // <NodeViewWrapper> measures the available area and exposes
-  // --embed-width / --embed-shift / --embed-pad. We extend the
-  // toolbar and grid sections out to the full available width via
-  // those vars, then re-pad the inner content so it visually aligns
-  // with page text. Sticky inset-inline-start keeps the toolbar
-  // pinned to the page-content edge during horizontal scroll.
-  const extendStyle = embedded
+  // When embedded inline in a doc page, the parent <NodeViewWrapper>
+  // exposes --embed-extend-l / --embed-extend-r (positive px values).
+  // We pull the grid's left/right edges outward via negative margin —
+  // box-model: width: auto becomes parent_width + extend, so the box
+  // physically grows past its parent's bounds. The toolbar keeps the
+  // parent-constrained width so it stays in line with the page text.
+  const gridExtendStyle = embedded
     ? ({
-        position: "relative",
-        width: "var(--embed-width, 100%)",
-        insetInlineStart: "var(--embed-shift, 0px)",
-        paddingInline: "var(--embed-pad, 0px)",
-      } as const)
-    : undefined;
-
-  const stickyToolbarStyle = embedded
-    ? ({
-        position: "sticky",
-        insetInlineStart: 0,
-        zIndex: 4,
+        marginLeft: "calc(-1 * var(--embed-extend-l, 0px))",
+        marginRight: "calc(-1 * var(--embed-extend-r, 0px))",
       } as const)
     : undefined;
 
@@ -346,29 +335,25 @@ export function BaseTable({ pageId, embedded }: BaseTableProps) {
         height: embedded ? "auto" : "100%",
       }}
     >
-      <div style={extendStyle}>
-        <BaseViewDraftBanner
-          isDirty={isDirty}
-          canSave={canSave}
-          onReset={resetDraft}
-          onSave={handleSaveDraft}
-          saving={updateViewMutation.isPending}
-        />
-        <div style={stickyToolbarStyle}>
-          <BaseToolbar
-            base={base}
-            activeView={effectiveView}
-            views={views}
-            table={table}
-            onViewChange={handleViewChange}
-            onAddView={handleAddView}
-            onPersistViewConfig={persistViewConfig}
-            onDraftSortsChange={handleDraftSortsChange}
-            onDraftFiltersChange={handleDraftFiltersChange}
-          />
-        </div>
-      </div>
-      <div style={extendStyle}>
+      <BaseViewDraftBanner
+        isDirty={isDirty}
+        canSave={canSave}
+        onReset={resetDraft}
+        onSave={handleSaveDraft}
+        saving={updateViewMutation.isPending}
+      />
+      <BaseToolbar
+        base={base}
+        activeView={effectiveView}
+        views={views}
+        table={table}
+        onViewChange={handleViewChange}
+        onAddView={handleAddView}
+        onPersistViewConfig={persistViewConfig}
+        onDraftSortsChange={handleDraftSortsChange}
+        onDraftFiltersChange={handleDraftFiltersChange}
+      />
+      <div style={gridExtendStyle}>
         <GridContainer
           table={table}
           properties={base.properties}

apps/client/src/features/editor/components/base-embed/base-embed-view.tsx

@@ -4,43 +4,40 @@ import { useEffect, useRef } from "react";
 import { BaseTable } from "@/features/base/components/base-table";
 import { useBaseQuery } from "@/features/base/queries/base-query";
 
-const SIDE_GUTTER = 8;
+const RIGHT_GUTTER = 16;
+const LEFT_GUTTER = 8;
 
-// Walk up from `el` to find the closest ancestor that's meaningfully
-// wider than `el` itself. That ancestor is the available drawing area
-// our embed should expand into (e.g. AppShell.Main when the page sits
-// inside a 900px Mantine Container). Returns null if no such ancestor
-// exists — the embed then renders without extension.
-function findWiderAncestor(el: HTMLElement): HTMLElement | null {
-  const baseWidth = el.getBoundingClientRect().width;
-  let cur: HTMLElement | null = el.parentElement;
+// Measure how far we can extend the grid past the wrapper's natural
+// (parent-constrained) bounds, and write the values as CSS vars on the
+// wrapper so the descendant grid can consume them via margin.
+function applyExtension(wrapper: HTMLDivElement) {
+  const rect = wrapper.getBoundingClientRect();
+  if (rect.width === 0) return;
+
+  const extendRight = Math.max(
+    0,
+    window.innerWidth - rect.right - RIGHT_GUTTER,
+  );
+
+  // Find the leftmost the grid can reach: walk up the ancestor chain
+  // for the closest element wider than the wrapper. That ancestor's
+  // left edge (plus a small gutter) is our left target. This handles
+  // the sidebar-collapsed case naturally — the wider ancestor is
+  // AppShell.Main, whose left edge moves when the sidebar toggles.
+  let targetLeft = rect.left;
+  let cur: HTMLElement | null = wrapper.parentElement;
   while (cur && cur !== document.body) {
-    const w = cur.getBoundingClientRect().width;
-    if (w > baseWidth + 32) return cur;
+    const r = cur.getBoundingClientRect();
+    if (r.width > rect.width + 32) {
+      targetLeft = r.left + LEFT_GUTTER;
+      break;
+    }
     cur = cur.parentElement;
   }
-  return null;
-}
+  const extendLeft = Math.max(0, rect.left - targetLeft);
 
-function applyExtension(wrapper: HTMLDivElement) {
-  const wrapperRect = wrapper.getBoundingClientRect();
-  if (wrapperRect.width === 0) return;
-  const wider = findWiderAncestor(wrapper);
-  if (!wider) {
-    wrapper.style.setProperty("--embed-shift", "0px");
-    wrapper.style.setProperty("--embed-width", "100%");
-    wrapper.style.setProperty("--embed-pad", "0px");
-    return;
-  }
-  const widerRect = wider.getBoundingClientRect();
-  const targetLeft = widerRect.left + SIDE_GUTTER;
-  const targetWidth = widerRect.width - SIDE_GUTTER * 2;
-  const shift = targetLeft - wrapperRect.left;
-  wrapper.style.setProperty("--embed-shift", `${shift}px`);
-  wrapper.style.setProperty("--embed-width", `${targetWidth}px`);
-  // Re-pad inner content back to the original wrapper bounds so
-  // toolbar buttons / first column visually align with page text.
-  wrapper.style.setProperty("--embed-pad", `${-shift}px`);
+  wrapper.style.setProperty("--embed-extend-r", `${extendRight}px`);
+  wrapper.style.setProperty("--embed-extend-l", `${extendLeft}px`);
 }
 
 export function BaseEmbedView({ node }: NodeViewProps) {
@@ -57,8 +54,17 @@ export function BaseEmbedView({ node }: NodeViewProps) {
 
     const ro = new ResizeObserver(update);
     ro.observe(wrapper);
-    const wider = findWiderAncestor(wrapper);
-    if (wider) ro.observe(wider);
+    // Also observe an ancestor so sidebar collapse / window changes
+    // propagate even when the wrapper itself doesn't resize.
+    let cur: HTMLElement | null = wrapper.parentElement;
+    while (cur && cur !== document.body) {
+      const r = cur.getBoundingClientRect();
+      if (r.width > wrapper.getBoundingClientRect().width + 32) {
+        ro.observe(cur);
+        break;
+      }
+      cur = cur.parentElement;
+    }
 
     window.addEventListener("resize", update);
     return () => {