Fix streaming: resolve scripts inside </body>, live server tests

The shell HTML included closing </body></html> tags. Resolve script
chunks arrived AFTER the document end — browser ignored them
(ERR_INCOMPLETE_CHUNKED_ENCODING). Now strips </body></html> from
shell, sends resolve scripts inside the body, closes document last.

Added live server Playwright tests that hit the actual streaming
endpoint and verify suspense slots resolve with content.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

hosts/ocaml/bin/sx_server.ml

@@ -2079,11 +2079,30 @@ let http_render_page_streaming env path _headers fd page_name =
   in
   let t1 = Unix.gettimeofday () in
 
-  (* Phase 2: Send chunked header + shell HTML *)
+  (* Phase 2: Send chunked header + shell HTML.
+     Strip closing </body></html> from shell — resolve scripts must go INSIDE
+     the body, otherwise the browser's HTML parser ignores them. *)
+  let shell_body, shell_tail =
+    (* Find last </body> and split there *)
+    let s = shell_html in
+    let body_close = "</body>" in
+    let rec find_last i found =
+      if i < 0 then found
+      else if i + String.length body_close <= String.length s
+              && String.sub s i (String.length body_close) = body_close
+      then find_last (i - 1) i
+      else find_last (i - 1) found
+    in
+    let pos = find_last (String.length s - String.length body_close) (-1) in
+    if pos >= 0 then
+      (String.sub s 0 pos, String.sub s pos (String.length s - pos))
+    else
+      (s, "")
+  in
   let header = http_chunked_header () in
   let header_bytes = Bytes.of_string header in
   (try ignore (Unix.write fd header_bytes 0 (Bytes.length header_bytes)) with _ -> ());
-  write_chunk fd shell_html;
+  write_chunk fd shell_body;
   (* Bootstrap resolve script — must come after shell so suspense elements exist *)
   write_chunk fd _sx_streaming_bootstrap;
   let t2 = Unix.gettimeofday () in
@@ -2170,7 +2189,8 @@ let http_render_page_streaming env path _headers fd page_name =
   end else
     Printf.eprintf "[sx-stream] %s shell=%.3fs (no :data/:content)\n%!" path (t1 -. t0);
 
-  (* Phase 4: End chunked response *)
+  (* Phase 4: Send closing tags + end chunked response *)
+  if shell_tail <> "" then write_chunk fd shell_tail;
   end_chunked fd
 
 (* ====================================================================== *)

tests/playwright/streaming.spec.js

@@ -386,3 +386,46 @@ test.describe('Streaming sandbox', () => {
     await expect(page.locator('[data-suspense="stream-slow"]')).toContainText('~5s');
   });
 });
+
+// =========================================================================
+// Live server tests — verify the actual chunked response works end-to-end
+// =========================================================================
+const BASE_URL = process.env.SX_TEST_URL || 'http://localhost:8013';
+
+test.describe('Streaming live server', () => {
+  test.describe.configure({ timeout: 30000 });
+
+  test('streaming page resolves suspense slots from server', async ({ page }) => {
+    // Load the streaming page from the actual server
+    await page.goto(BASE_URL + '/sx/(geography.(isomorphism.streaming))', {
+      waitUntil: 'networkidle',
+      timeout: 20000,
+    });
+
+    // Should have 3 suspense slots
+    await expect(page.locator('[data-suspense]')).toHaveCount(3);
+
+    // All 3 slots should have resolved content (not empty, not just skeletons)
+    await expect(page.locator('[data-suspense="stream-fast"]')).toContainText('Fast source', { timeout: 15000 });
+    await expect(page.locator('[data-suspense="stream-medium"]')).toContainText('Medium source', { timeout: 15000 });
+    await expect(page.locator('[data-suspense="stream-slow"]')).toContainText('Slow source', { timeout: 15000 });
+  });
+
+  test('no chunked encoding errors in console', async ({ page }) => {
+    const errors = [];
+    page.on('pageerror', e => errors.push(e.message));
+    page.on('console', msg => {
+      if (msg.type() === 'error') errors.push(msg.text());
+    });
+
+    await page.goto(BASE_URL + '/sx/(geography.(isomorphism.streaming))', {
+      waitUntil: 'networkidle',
+      timeout: 20000,
+    });
+
+    // Filter for chunked encoding errors specifically
+    const chunkErrors = errors.filter(e =>
+      e.includes('CHUNKED') || e.includes('INCOMPLETE') || e.includes('ERR_EMPTY'));
+    expect(chunkErrors).toEqual([]);
+  });
+});