add state_get/state_set builtins for frame-persistent key-value store

bin/el/src/main.rs

@@ -2322,7 +2322,9 @@ fn dispatch_builtin(
                         "Content-Type", content_type
                     ).unwrap();
                     if let Some(dir) = html_dir {
-                        let asset_path = dir.join(file_name);
+                        // Try src/assets/<file> first, then src/<file> as fallback
+                        let asset_path = dir.join("assets").join(file_name);
+                        let asset_path = if asset_path.exists() { asset_path } else { dir.join(file_name) };
                         if let Ok(bytes) = std::fs::read(&asset_path) {
                             let _ = request.respond(
                                 tiny_http::Response::from_data(bytes)
@@ -4551,6 +4553,27 @@ fn dispatch_builtin(
             BuiltinResult::Handled
         }
 
+        // ── Frame-persistent key-value state ────────────────────────────────
+        // state_set / state_get use GLOBAL_STATE so values survive between frames
+        // when canvas_run_loop calls the draw function repeatedly.
+
+        "state_set" => {
+            // state_set(key: String, val: String) -> Void
+            let val = match stack.pop().unwrap_or(Value::Nil) { Value::Str(s) => s, _ => String::new() };
+            let key = match stack.pop().unwrap_or(Value::Nil) { Value::Str(s) => s, _ => String::new() };
+            GLOBAL_STATE.with(|gs| gs.borrow_mut().insert(key, val));
+            stack.push(Value::Nil);
+            BuiltinResult::Handled
+        }
+
+        "state_get" => {
+            // state_get(key: String) -> String
+            let key = match stack.pop().unwrap_or(Value::Nil) { Value::Str(s) => s, _ => String::new() };
+            let val = GLOBAL_STATE.with(|gs| gs.borrow().get(&key).cloned().unwrap_or_default());
+            stack.push(Value::Str(val));
+            BuiltinResult::Handled
+        }
+
         "canvas_run_loop" => {
             // canvas_run_loop(draw_fn: String) -> Void  (never returns)
             let draw_fn = match stack.pop().unwrap_or(Value::Nil) { Value::Str(s) => s, _ => "draw".into() };