feat(data-table): add declarative cell-editing errors

.changeset/quiet-cell-errors.md

@@ -0,0 +1,67 @@
+---
+"@tailor-platform/app-shell": minor
+---
+
+Add built-in error popovers to DataTable inline editing. When `onValueChange` or `onValueCommitted` throws or returns a rejected Promise, the affected cell shows an error. Throw the exported `CellEditError` with a translated, user-facing message to display that text; other failures display the localized message “Could not confirm this change”.
+
+Alongside this feedback, the editor now retains pending and failed drafts for correction or retry. Confirmation waits for any pending `onValueChange` check to succeed, and the draft clears only after confirmation succeeds. Drafts remain editable without trapping cell navigation. For direct inputs, Tab and Shift+Tab retain an already failed commit without retrying it; press Enter to retry. Data adoption, persistence, and rollback remain consumer-owned.
+
+Each new failure automatically opens its popover without moving focus. Closing the details retains the draft and error, which can be inspected again with the error icon or Alt+ArrowDown. Tab or Shift+Tab to another cell or out of the table dismisses the details without trapping focus; Tab within interactive error content remains available. Esc closes open details first; a subsequent Esc discards the draft and error together. The standard popover adds no reset action.
+
+For example, reject negative quantities with a user-facing message. Invalid drafts remain editable; successful confirmation updates the consumer-owned rows:
+
+```tsx
+import { useState } from "react";
+import {
+  CellEditError,
+  DataTable,
+  createColumnHelper,
+  useDataTable,
+} from "@tailor-platform/app-shell";
+
+type Item = { id: string; quantity: number | null };
+const { column } = createColumnHelper<Item>();
+
+function EditableItems() {
+  const [rows, setRows] = useState<Item[]>([{ id: "item-1", quantity: 5 }]);
+  const columns = [
+    column({
+      id: "quantity",
+      label: "Quantity",
+      type: "number",
+      edit: {
+        onValueCommitted: (row, value) => {
+          if (value !== null && value < 0) {
+            throw new CellEditError("Quantity must be zero or greater");
+          }
+          setRows((current) =>
+            current.map((item) => (item.id === row.id ? { ...item, quantity: value } : item)),
+          );
+        },
+      },
+    }),
+  ];
+  const table = useDataTable({ columns, data: { rows } });
+
+  return (
+    <DataTable.Root value={table}>
+      <DataTable.Table />
+    </DataTable.Root>
+  );
+}
+```
+
+The standard error popover needs no configuration. To customize its body or include consumer-owned actions, add `error.render` to the column's `edit` config. The renderer receives the current row and the original thrown value:
+
+```tsx
+error: {
+  render: ({ row, error }) => (
+    <div>
+      <p>Could not update item {row.id}</p>
+      <p>{error instanceof CellEditError ? error.message : "Please try again later"}</p>
+    </div>
+  ),
+},
+```
+
+If the callback handles its own failures and feedback instead, set `edit.error: false` to disable callback interception and retain eager edit completion.

docs-manifest.json

@@ -412,6 +412,7 @@
       "symbols": [
         "BadgeCellEditOptions",
         "BuildQueryVariables",
+        "CellEditError",
         "CellEditState",
         "CollectionControl",
         "CollectionControlProvider",
@@ -471,10 +472,10 @@
         "withURLCollectionState"
       ],
       "hashes": {
-        "typeSurface": "05cbf8a4bdb7a863",
-        "outline": "93a2a1e3c380f5b9",
+        "typeSurface": "33eb2bdd6be1c774",
+        "outline": "8ca624c7ec761939",
         "snapshot": "a97e067c66e46ef6",
-        "outputMd": "94d4e9340fdb20f3",
+        "outputMd": "b1ee3ccb6cb4a1f4",
         "examples": "10abd548e6affb9d"
       }
     },
@@ -1786,7 +1787,7 @@
     "packages/core/skills/app-shell-patterns/references/components/combobox.md": "dfb775c7c4307409",
     "packages/core/skills/app-shell-patterns/references/components/command-palette.md": "7e5bc675a593791a",
     "packages/core/skills/app-shell-patterns/references/components/csv-importer.md": "53d3c795ca21b9dc",
-    "packages/core/skills/app-shell-patterns/references/components/data-table.md": "94d4e9340fdb20f3",
+    "packages/core/skills/app-shell-patterns/references/components/data-table.md": "b1ee3ccb6cb4a1f4",
     "packages/core/skills/app-shell-patterns/references/components/date-picker.md": "bc69f14829004f9d",
     "packages/core/skills/app-shell-patterns/references/components/default-header.md": "375e55f4b12fa2be",
     "packages/core/skills/app-shell-patterns/references/components/default-sidebar.md": "3422388a0cc78571",