Initial commit: restructure to flat layout with ui/ and web/ at root

web/server/lib/github/device-flow.js

@@ -0,0 +1,50 @@
+const DEVICE_CODE_URL = 'https://github.com/login/device/code';
+const ACCESS_TOKEN_URL = 'https://github.com/login/oauth/access_token';
+const DEVICE_GRANT_TYPE = 'urn:ietf:params:oauth:grant-type:device_code';
+
+const encodeForm = (params) => {
+  const body = new URLSearchParams();
+  for (const [key, value] of Object.entries(params)) {
+    if (value == null) continue;
+    body.set(key, String(value));
+  }
+  return body.toString();
+};
+
+async function postForm(url, params) {
+  const response = await fetch(url, {
+    method: 'POST',
+    headers: {
+      'Content-Type': 'application/x-www-form-urlencoded',
+      Accept: 'application/json',
+    },
+    body: encodeForm(params),
+  });
+
+  const payload = await response.json().catch(() => null);
+  if (!response.ok) {
+    const message = payload?.error_description || payload?.error || response.statusText;
+    const error = new Error(message || 'GitHub request failed');
+    error.status = response.status;
+    error.payload = payload;
+    throw error;
+  }
+  return payload;
+}
+
+export async function startDeviceFlow({ clientId, scope }) {
+  return postForm(DEVICE_CODE_URL, {
+    client_id: clientId,
+    scope,
+  });
+}
+
+export async function exchangeDeviceCode({ clientId, deviceCode }) {
+  // GitHub returns 200 with {error: 'authorization_pending'|...} for non-success states.
+  const payload = await postForm(ACCESS_TOKEN_URL, {
+    client_id: clientId,
+    device_code: deviceCode,
+    grant_type: DEVICE_GRANT_TYPE,
+  });
+  return payload;
+}