docs: the container reference and the layout guide state the twelve padding steps; changeset

Claude-Session: https://claude.ai/code/session_01XvhGmGAP79ZB8swnkapxPC
Co-authored-by: Claude <noreply@anthropic.com>

Author: claude

.changeset/11424-container-padding-set.md

@@ -0,0 +1,27 @@
+---
+'@object-ui/types': minor
+'@object-ui/components': minor
+---
+
+A `container` node's `padding` is one of the twelve steps its renderer maps: 0 to 8, 10, 12
+and 16. Any other number is refused at validation, with the set named (objectui#11424).
+
+**Breaking for a `container` that carries any other `padding` number.** The key was declared
+as any number, but the `container` renderer has one padding class per step and nothing for
+the rest. So `padding: 9` or `padding: 20` parsed clean and the container rendered with no
+padding class at all, not even the default `4`, because the default applies only when the key
+is absent.
+
+- `@object-ui/types`: `ContainerSchema.padding` is the literal union
+  `0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 16` on the TypeScript face, so `tsc` refuses
+  any other number. The zod mirror refuses one at `padding` (`invalid_value`, with the twelve
+  values in the issue), with a message that lists the set. `safeValidateSchema` (what
+  `objectui validate` runs) and the strict authoring face both give that refusal.
+- `@object-ui/components`: the `container` registration's `padding` input changes from
+  `type: 'number'` to a closed `enum` of the same twelve numbers, in the object form
+  `maxWidth` already uses. In the SDUI manifest, `validateTree` now answers an unlisted number
+  with `invalid-enum`, and the generated intrinsics type the prop as the twelve literals. The
+  renderer is unchanged: it does not round or clamp, and an absent key still renders the
+  default step `4`.
+
+Migration: replace the number with the step you meant from the set. `0` means no padding.

content/docs/components/layout/container.mdx

@@ -22,7 +22,13 @@ interface ContainerSchema {
   maxWidth?: 'sm' | 'md' | 'lg' | 'xl' | '2xl' | '3xl' | '4xl' | '5xl' | '6xl'
     | '7xl' | 'full' | 'screen' | false;   // default: 'xl'
   centered?: boolean;                       // default: true
-  padding?: number;                         // 0, 1-8, 10, 12, 16 — default: 4
+  padding?: 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 10 | 12 | 16;  // default: 4
   className?: string;
 }
 ```
+
+`padding` is a step on the container's spacing scale, and `0` means none. The twelve
+steps are the ones the renderer maps to a padding class, so they are the only values
+validation accepts: `"padding": 9` or `"padding": 20` is refused with the set named
+(objectui#11424). Such a number used to pass validation and then render with no padding
+at all, not even the default.

content/docs/guide/layout.md

@@ -712,7 +712,8 @@ the sidebar are nodes you build, so style them where you build them, as above.
 
 A `page` node has no padding switch. Its wrapper always insets the content: `p-3`, then
 `md:p-4`, then `lg:p-6`. The padding you control is a `container`'s. Its `padding` is a
-number on the container's spacing scale, and `0` means none:
+step on the container's spacing scale: one of 0 to 8, 10, 12 or 16, and `0` means none.
+Any other number is refused:
 
 ```json
 {