fix(spec): don't require slots on slotted pages (#2261)

`PageSchema`'s superRefine rejected any `kind: 'slotted'` page without a
`slots` map. But a slotted page with no overrides is valid and useful — every
slot falls through to the synthesized default layout, the natural starting
point before you add overrides. Requiring `slots` up front made the Studio
"New Page" form a dead-end the instant you picked "slotted" (the form can't
author a slot map), the same trap as the old required `regions`. Removed the
superRefine clause; `slots` stays optional.

Found by dogfooding the Studio page designer. Verified: slotted-without-slots
now parses; 86 page tests pass.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: os-zhuang

.changeset/slotted-page-no-slots-required.md

@@ -0,0 +1,12 @@
+---
+"@objectstack/spec": patch
+---
+
+fix(spec): don't require `slots` on slotted pages
+
+`PageSchema`'s superRefine rejected any `kind: 'slotted'` page that didn't
+provide a `slots` map — but a slotted page with no overrides is valid: every
+slot falls through to the synthesized default layout, the natural starting
+point before you add overrides. Requiring `slots` up front made the Studio
+"New Page" form a dead-end the moment you picked "slotted" (the form can't
+author a slot map), the same trap as the old required `regions`.

packages/spec/src/ui/page.zod.ts

@@ -415,13 +415,12 @@ export const PageSchema = lazySchema(() => z.object({
       message: 'blankLayout is required when type is "blank"',
     });
   }
-  if (data.kind === 'slotted' && !data.slots) {
-    ctx.addIssue({
-      code: z.ZodIssueCode.custom,
-      path: ['slots'],
-      message: 'slots is required when kind is "slotted"',
-    });
-  }
+  // NOTE: `kind: 'slotted'` does NOT require `slots`. A slotted page with no
+  // overrides renders the synthesized default layout (every slot falls through
+  // to the default) — the natural starting point: create the slotted shell,
+  // then add slot overrides in the editor. Requiring `slots` up front made the
+  // Studio "New Page" form a dead-end the moment you picked "slotted" (the form
+  // can't author a slot map), the same trap as the old required `regions`.
 }));
 
 export type Page = z.infer<typeof PageSchema>;