feat: replace the ssr/client data blocks with apis blocks

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

packages/syntax/test/apis-block.test.ts

@@ -74,28 +74,12 @@ test("a bare body inside apis {} is a parse error naming response", () => {
   expect(() => parse(page(`    bare GET /api/z { return data }`))).toThrow(/response/i);
 });
 
-test("apis entry followed by an ssr api of the same name is rejected", () => {
+test("two apis entries of the same name across separate blocks are rejected", () => {
   const src = `page Repro {
   apis {
     foo GET /api/foo { response { return data } }
   }
 
-  ssr {
-    api foo GET /api/foo { return data }
-  }
-
-  view { <main>x</main> }
-}
-`;
-  expect(() => parse(src)).toThrow(/duplicate/i);
-});
-
-test("ssr api followed by an apis entry of the same name is rejected", () => {
-  const src = `page Repro {
-  ssr {
-    api foo GET /api/foo { return data }
-  }
-
   apis {
     foo GET /api/foo { response { return data } }
   }