fix(control-plane): bridge whynot-design forms into native submission

wn-input/wn-select/wn-button aren't form-associated custom elements —
their real <input>/<select>/<button> live inside shadow DOM, invisible
to an ancestor <form>. Clicking Sign In (or any wn-button[type=submit])
silently did nothing, and even a submitted form would have carried none
of the field values. Bridges both gaps generically in base.html without
touching the vendored library: mirrors each shadow-DOM control's live
value into a hidden native input on submit, and explicitly calls
form.requestSubmit() on wn-button[type=submit] clicks.

Reported by the user clicking Sign In in the running local instance —
missed by test_control_plane_app.py because TestClient POSTs directly
and never exercises real button clicks or shadow DOM.

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

src/target_revenue/service/control_plane_templates/base.html

@@ -50,5 +50,47 @@
   Visual language vendored from <code>whynot-design</code> — see
   <code>static/whynot-design/VENDORED.md</code>.
 </p>
+
+<script>
+// whynot-design's wn-input/wn-select/wn-textarea/wn-button are plain Lit
+// components, not form-associated custom elements — their real <input>/
+// <select>/<button> live inside shadow DOM, invisible to an ancestor
+// <form>. Without this, clicking a wn-button[type=submit] does nothing,
+// and even if it did, none of the field values would be part of the POST.
+// This bridges both gaps generically, for every .wn-form on every page,
+// without touching the vendored library itself.
+(function () {
+  function readValue(el) {
+    var native = el.shadowRoot && el.shadowRoot.querySelector("input, select, textarea");
+    return native ? native.value : (el.value != null ? el.value : "");
+  }
+
+  document.querySelectorAll("form").forEach(function (form) {
+    form.addEventListener("submit", function () {
+      form.querySelectorAll("[name]").forEach(function (el) {
+        if (!el.tagName || el.tagName.indexOf("WN-") !== 0) return;
+        var name = el.getAttribute("name");
+        if (!name) return;
+        var hidden = form.querySelector('input[type="hidden"][data-wn-mirror-for="' + name + '"]');
+        if (!hidden) {
+          hidden = document.createElement("input");
+          hidden.type = "hidden";
+          hidden.name = name;
+          hidden.dataset.wnMirrorFor = name;
+          form.appendChild(hidden);
+        }
+        hidden.value = readValue(el);
+      });
+    });
+
+    form.querySelectorAll("wn-button[type=submit]").forEach(function (btn) {
+      btn.addEventListener("click", function () {
+        if (typeof form.requestSubmit === "function") form.requestSubmit();
+        else form.submit();
+      });
+    });
+  });
+})();
+</script>
 </body>
 </html>

tests/test_control_plane_app.py

@@ -287,3 +287,19 @@ def test_audit_log_visible_to_signed_in_user(client, credentials):
     _login(client, credentials["viewer"].token)
     resp = client.get("/audit")
     assert resp.status_code == 200
+
+
+def test_form_bridge_script_present(client):
+    """whynot-design's wn-input/wn-select/wn-button are not
+    form-associated custom elements — their real <input>/<select>/
+    <button> live inside shadow DOM, invisible to an ancestor <form>. A
+    plain click on wn-button[type=submit] silently does nothing, and
+    even a submitted form would carry none of the field values. This
+    only regressed once (base.html's bridging script), so pin its
+    presence — TestClient can't click a real button/shadow DOM, this is
+    the closest offline check available without a browser-automation
+    tool."""
+    resp = client.get("/login")
+    assert "wn-button[type=submit]" in resp.text
+    assert "requestSubmit" in resp.text
+    assert "data-wn-mirror-for" in resp.text