Add stubs for the frontier API used by the client

This is the support desk functions, although this doesn't work quite yet
and the game complains that it can't recieve any data.

src/bin/kawari-frontier.rs

@@ -1,5 +1,11 @@
-use axum::{Json, Router, routing::get};
+use axum::{
+    Json, Router,
+    http::{HeaderValue, Uri},
+    response::{IntoResponse, Response},
+    routing::{get, post},
+};
 use kawari::config::get_config;
+use reqwest::{StatusCode, header};
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -65,6 +71,67 @@ async fn get_headline() -> Json<Headline> {
     })
 }
 
+async fn fallback(uri: Uri) -> (StatusCode, String) {
+    tracing::warn!("{}", uri);
+    (StatusCode::NOT_FOUND, format!("No route for {uri}"))
+}
+
+#[derive(Clone, Copy, Debug)]
+#[must_use]
+
+pub struct Xml<T>(pub T);
+
+impl<T> IntoResponse for Xml<T>
+where
+    T: IntoResponse,
+{
+    fn into_response(self) -> Response {
+        (
+            [(header::CONTENT_TYPE, HeaderValue::from_static("text/xml"))],
+            self.0,
+        )
+            .into_response()
+    }
+}
+
+impl<T> From<T> for Xml<T> {
+    fn from(inner: T) -> Self {
+        Self(inner)
+    }
+}
+
+async fn session_get_init() -> Xml<String> {
+    // TODO: just a guess
+    Xml("<result>
+<return_code>OK</return_code>
+<information/>
+<inquiry_categoryList/>
+<inquiry_itemList/>
+<report_itemList/>
+</result>"
+        .to_string())
+}
+
+async fn view_get_init() -> Xml<String> {
+    Xml("<result>
+<return_code>OK</return_code>
+<information/>
+<inquiry_categoryList/>
+<inquiry_itemList/>
+<report_itemList/>
+</result>"
+        .to_string())
+}
+
+async fn get_headline_all() -> Xml<String> {
+    Xml("<result>
+<return_code>OK</return_code>
+<information>
+</information>
+</result>"
+        .to_string())
+}
+
 #[tokio::main]
 async fn main() {
     tracing_subscriber::fmt::init();
@@ -72,7 +139,21 @@ async fn main() {
     let app = Router::new()
         .route("/worldStatus/gate_status.json", get(get_world_status))
         .route("/worldStatus/login_status.json", get(get_login_status))
-        .route("/news/headline.json", get(get_headline));
+        .route("/news/headline.json", get(get_headline))
+        // used by the client
+        .route(
+            "/frontier-api/ffxivsupport/session/get_init",
+            post(session_get_init),
+        )
+        .route(
+            "/frontier-api/ffxivsupport/view/get_init",
+            get(view_get_init),
+        )
+        .route(
+            "/frontier-api/ffxivsupport/information/get_headline_all",
+            get(get_headline_all),
+        )
+        .fallback(fallback);
 
     let config = get_config();