fix(spec): make page regions and component properties optional

Two required-but-unauthorable fields made it impossible to create
record/home/app pages in the Studio metadata editor:

- `PageSchema.regions` was required, but the New Page form has no region
  editor and list/interface pages don't use regions at all — forcing
  `regions: []` boilerplate on every page and a hard dead-end for the rest.
- `PageComponentSchema.properties` was required, but the create-form seeds a
  record page's layout from the object's synthesized default page
  (buildDefaultPageSchema), whose nodes carry props at the top level — so
  every seeded block failed with
  "regions.N.components.M.properties: expected record". Many components
  (record:activity, element:divider, …) also legitimately carry no props.

Both become `.optional().default(...)`; an empty full page falls back to the
synthesized default layout, slotted pages compose via `slots`, and list pages
ignore regions. Also drops the now-unneeded `required` flag on the page form's
regions repeater and updates the three tests that asserted the old contract.

Verified end-to-end: a record page now creates successfully through the
Studio form. 802 spec UI tests + spec/platform-objects typechecks green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: os-zhuang

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

@@ -62,7 +62,11 @@ export const pageForm = defineForm({
       // the region designer is irrelevant here, so hide it for list pages.
       visibleOn: "data.type != 'list'",
       fields: [
-        { field: 'regions', type: 'repeater', required: true, helpText: 'Layout regions (header, main, sidebar, footer) with components' },
+        // Not required: an empty full page falls back to the synthesized default
+        // layout, slotted pages compose via `slots`, and list pages ignore regions
+        // entirely. Marking it required made the form unsatisfiable when no region
+        // editor was rendered (the metadata form can't yet edit a region tree).
+        { field: 'regions', type: 'repeater', helpText: 'Layout regions (header, main, sidebar, footer) with components' },
       ],
     },
     {

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

@@ -403,10 +403,9 @@ describe('PageSchema', () => {
       regions: [],
     })).toThrow();
 
-    expect(() => PageSchema.parse({
-      name: 'test_page',
-      label: 'Test Page',
-    })).toThrow();
+    // `regions` is intentionally NOT among the required fields — name + label
+    // alone is a valid page (regions defaults to [], type defaults to 'record').
+    // See the dedicated "accept page without regions" test below.
   });
 
   it('should reject invalid page type', () => {
@@ -1169,11 +1168,17 @@ describe('PageSchema - Negative Validation', () => {
     })).toThrow();
   });
 
-  it('should reject page without regions', () => {
-    expect(() => PageSchema.parse({
+  it('should accept page without regions (defaults to [])', () => {
+    // Optional with a [] default: list/interface pages render via
+    // interfaceConfig, slotted record pages via slots, and an empty full
+    // record/home/app page falls back to the synthesized default layout.
+    // Requiring regions forced `regions: []` boilerplate everywhere and made
+    // the Studio "New Page" form a dead-end for non-list pages.
+    const page = PageSchema.parse({
       name: 'no_regions',
       label: 'No Regions',
-    })).toThrow();
+    });
+    expect(page.regions).toEqual([]);
   });
 
   it('should reject page with camelCase name', () => {
@@ -1201,10 +1206,14 @@ describe('PageComponentSchema - Negative Validation', () => {
     })).toThrow();
   });
 
-  it('should reject component without properties', () => {
-    expect(() => PageComponentSchema.parse({
-      type: 'record:details',
-    })).toThrow();
+  it('should accept a component without properties (defaults to {})', () => {
+    // `properties` is optional with a {} default: many components carry no
+    // props (record:activity, element:divider) and the default-page
+    // synthesizer emits prop-at-top-level nodes. Requiring it broke seeding a
+    // record page's default layout in Studio (every block tripped
+    // "components.N.properties: expected record").
+    const comp = PageComponentSchema.parse({ type: 'record:details' });
+    expect(comp.properties).toEqual({});
   });
 });
 

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

@@ -74,7 +74,15 @@ export const PageComponentSchema = lazySchema(() => z.object({
 
   /** Configuration */
   label: I18nLabelSchema.optional(),
-  properties: z.record(z.string(), z.unknown()).describe('Component props passed to the widget. See component.zod.ts for schemas.'),
+  // Optional with an empty-object default. Many components carry no props
+  // (record:activity, element:divider, …), and the platform's own default-page
+  // synthesizer (buildDefaultPageSchema) emits nodes with props at the top
+  // level rather than under `properties`. Requiring `properties` forced
+  // `properties: {}` boilerplate and — worse — made every Studio attempt to
+  // seed a record page from its object's synthesized default layout fail
+  // validation ("regions.N.components.M.properties: expected record"), which
+  // was the real reason record/home/app pages couldn't be created in Studio.
+  properties: z.record(z.string(), z.unknown()).optional().default({}).describe('Component props passed to the widget. See component.zod.ts for schemas.'),
 
   /** 
    * Event Handlers 
@@ -332,7 +340,16 @@ export const PageSchema = lazySchema(() => z.object({
   template: z.string().default('default').describe('Layout template name (e.g. "header-sidebar-main")'),
 
   /** Regions & Content */
-  regions: z.array(PageRegionSchema).describe('Defined regions with components'),
+  // Optional with an empty-array default. Not every page authors regions:
+  //   • list/interface pages render via `interfaceConfig` (regions unused);
+  //   • `kind: 'slotted'` record pages render via `slots`;
+  //   • a `kind: 'full'` record/home/app page with no regions falls back to
+  //     the synthesized default layout (same surface a slotted page starts from).
+  // Requiring it forced `regions: []` boilerplate on every list page and made
+  // the Studio "New Page" form a dead-end for record/home/app pages (the form
+  // has no region editor, so the required field could never be satisfied).
+  regions: z.array(PageRegionSchema).optional().default([])
+    .describe('Layout regions (header, main, sidebar, footer) with their components. Optional — list pages use interfaceConfig, slotted pages use slots, and an empty full page falls back to the synthesized default layout.'),
 
   /** Activation */
   isDefault: z.boolean().default(false),