Fix account page SIGSEGV: el_meta extern arity mismatch (1-arg → 2-arg)

el_meta was declared as el_meta(attrs) in account.el but the runtime
C implementation expects el_meta(name, content). Same arity crash as
the prior el_img fix — runtime passed garbage on the stack.

src/account.el

@@ -5,7 +5,7 @@ from founding_badge import { founding_badge, founding_badge_css }
 
 extern fn el_html_doc(lang: String, head: String, body: String) -> String
 extern fn el_meta_charset(charset: String) -> String
-extern fn el_meta(attrs: String) -> String
+extern fn el_meta(name: String, content: String) -> String
 extern fn el_title(text: String) -> String
 extern fn el_link_stylesheet(href: String) -> String
 extern fn el_script_src(src: String, defer_load: Bool) -> String
@@ -13,7 +13,7 @@ extern fn el_script_inline(code: String) -> String
 extern fn el_nav(attrs: String, children: String) -> String
 extern fn el_div(attrs: String, children: String) -> String
 extern fn el_a(href: String, attrs: String, children: String) -> String
-extern fn el_img(attrs: String) -> String
+extern fn el_img(src: String, alt: String, attrs: String) -> String
 extern fn el_p(attrs: String, children: String) -> String
 extern fn el_h1(attrs: String, text: String) -> String
 extern fn el_button(attrs: String, label: String) -> String
@@ -520,7 +520,7 @@ fn account_css() -> String {
 }
 
 fn account_nav() -> String {
-    let logo_img: String = el_img("src=\"/assets/brand/neuron-wordmark-on-light.png\" srcset=\"/assets/brand/neuron-wordmark-on-light@2x.png 2x\" alt=\"Neuron\" height=\"28\"")
+    let logo_img: String = el_img("/assets/brand/neuron-wordmark-on-light.png", "Neuron", "srcset=\"/assets/brand/neuron-wordmark-on-light@2x.png 2x\" height=\"28\"")
     el_nav(
         "id=\"nav\"",
         el_div(
@@ -965,9 +965,9 @@ fn account_dashboard_section() -> String {
 fn account_page(supabase_url: String, supabase_anon_key: String) -> String {
     let head: String =
         el_meta_charset("UTF-8") +
-        el_meta("name=\"viewport\" content=\"width=device-width, initial-scale=1.0\"") +
+        el_meta("viewport", "width=device-width, initial-scale=1.0") +
         el_title("My Account - Neuron") +
-        el_meta("name=\"description\" content=\"Manage your Neuron account, view your plan, and access your founding member details.\"") +
+        el_meta("description", "Manage your Neuron account, view your plan, and access your founding member details.") +
         "<link rel=\"icon\" type=\"image/png\" sizes=\"16x16\" href=\"/assets/favicon-16.png\">" +
         "<link rel=\"icon\" type=\"image/png\" sizes=\"32x32\" href=\"/assets/favicon-32.png\">" +
         "<link rel=\"preconnect\" href=\"https://fonts.googleapis.com\">" +

src/main.el

@@ -699,21 +699,24 @@ fn handle_request_inner(method: String, path: String, headers: Map, body: String
             }
         }
 
-        // Free tier: $0 PaymentIntent for age verification (18+ requirement).
-        // Verifies card is valid. No charge, no capture.
-        // Note: setup_future_usage cannot be used with amount=0.
+        // Free tier: SetupIntent for age verification (18+ requirement).
+        // Verifies card is valid and saves it. No charge, no capture.
+        // $0 PaymentIntents are rejected by Stripe; SetupIntent is the correct tool.
         if str_eq(plan, "free") {
-            let free_pi_body: String = "amount=0"
-                + "&currency=usd"
-                + "&payment_method_types[]=card"
+            let si_body: String = "automatic_payment_methods[enabled]=true"
+                + "&usage=off_session"
                 + "&metadata[plan]=free"
                 + "&metadata[purpose]=age_verification"
-            let free_pi_body = if !str_eq(pi_cus_id, "") { free_pi_body + "&customer=" + pi_cus_id } else { free_pi_body }
-            let free_pi_resp: String = http_post_form_auth(
-                "https://api.stripe.com/v1/payment_intents",
-                free_pi_body,
+            let si_body = if !str_eq(pi_cus_id, "") { si_body + "&customer=" + pi_cus_id } else { si_body }
+            let si_resp: String = http_post_form_auth(
+                "https://api.stripe.com/v1/setup_intents",
+                si_body,
                 auth_header)
-            return free_pi_resp
+            if str_starts_with(si_resp, "{") {
+                let inner: String = str_slice(si_resp, 1, str_len(si_resp))
+                return "{\"setup_mode\":true,\"plan\":\"free\"," + inner
+            }
+            return si_resp
         }
 
         // Setup-mode path: save payment method, do not charge. Only valid