Add cek-call, context primitive, forms.sx, regex-find-all stubs

- cek-call/cek-run: dispatch through Sx_ref.cek_call for signal tests
- context: registered as both env binding and Sx_primitives primitive
  so signals.sx can resolve it through the primitive table
- forms.sx: loaded before other web modules — provides defpage special
  form, stream-chunk-id, normalize-binding-key, etc.
- regex-find-all: substring-based stub for component scanning
- now-ms: stub returning 1000

1525 → 1578 passing tests (+53).

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

hosts/ocaml/bin/run_tests.ml

@@ -332,6 +332,14 @@ let make_test_env () =
       let stack = try Hashtbl.find _scope_stacks name with Not_found -> [] in
       (match stack with v :: _ -> v | [] -> Nil)
     | _ -> Nil);
+  let context_fn = (fun args ->
+    match args with
+    | String name :: rest ->
+      let stack = try Hashtbl.find _scope_stacks name with Not_found -> [] in
+      (match stack with v :: _ -> v | [] -> (match rest with d :: _ -> d | [] -> Nil))
+    | _ -> Nil) in
+  bind "context" context_fn;
+  Sx_primitives.register "context" context_fn;
   bind "scope-emit!" (fun args ->
     match args with
     | [String name; value] ->
@@ -398,6 +406,49 @@ let make_test_env () =
       eval_expr m.m_body (Env local)
     | _ -> raise (Eval_error "expand-macro: expected (macro args env)"));
 
+  bind "cek-call" (fun args ->
+    match args with
+    | [fn_val; List call_args] -> Sx_ref.cek_call fn_val (List call_args)
+    | [fn_val; ListRef { contents = call_args }] -> Sx_ref.cek_call fn_val (List call_args)
+    | [fn_val; Nil] -> Sx_ref.cek_call fn_val (List [])
+    | [fn_val] -> Sx_ref.cek_call fn_val (List [])
+    | _ -> Nil);
+  bind "cek-run" (fun args ->
+    match args with
+    | [state] -> Sx_ref.cek_run state
+    | _ -> Nil);
+  bind "now-ms" (fun _args -> Number 1000.0);
+  bind "regex-find-all" (fun args ->
+    (* Stub: supports simple ~name pattern for component scanning *)
+    match args with
+    | [String pattern; String text] ->
+      let prefix = if String.length pattern > 2 && pattern.[0] = '(' then
+        (* Extract literal prefix from pattern like "(~[a-z/.-]+" → "~" *)
+        let s = String.sub pattern 1 (String.length pattern - 1) in
+        let p = try String.sub s 0 (String.index s '[')
+                with Not_found -> try String.sub s 0 (String.index s '(')
+                with Not_found -> s in
+        if String.length p > 0 then p else "~"
+      else pattern in
+      let results = ref [] in
+      let len = String.length text in
+      let plen = String.length prefix in
+      let i = ref 0 in
+      while !i <= len - plen do
+        if String.sub text !i plen = prefix then begin
+          (* Find end of identifier *)
+          let j = ref (!i + plen) in
+          while !j < len && let c = text.[!j] in
+            (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')
+            || c = '-' || c = '/' || c = '_' || c = '.' do
+            incr j
+          done;
+          results := String (String.sub text !i (!j - !i)) :: !results;
+          i := !j
+        end else incr i
+      done;
+      List (List.rev !results)
+    | _ -> List []);
   bind "callable?" (fun args ->
     match args with
     | [NativeFn _] | [Lambda _] | [Component _] | [Island _] -> Bool true
@@ -962,6 +1013,7 @@ let run_spec_tests env test_files =
   load_module "adapter-html.sx" web_dir;
   load_module "adapter-sx.sx" web_dir;
   (* Web modules for web/tests/ *)
+  load_module "forms.sx" web_dir;
   load_module "engine.sx" web_dir;
   load_module "page-helpers.sx" web_dir;
   load_module "request-handler.sx" web_dir;