fix(desktop): route fetch + WebSocket through native Tauri plugins (mixed-content)

Fixing VITE_API_BASE got login to build a correct absolute URL, but it still
failed with WebKit's generic "Load failed" — WebKitGTK treats tauri://localhost
as a secure origin, so http://127.0.0.1:3000 (and ws://) from inside it is
blocked as mixed content, a WebKit limitation CSP's connect-src can't override.

Added tauri-plugin-http (genuine fetch() drop-in, wired via a new
platformFetch() in origin.ts, used by api.ts + logger.ts) and
tauri-plugin-websocket (not a drop-in — adapted behind a native-WebSocket-
shaped interface in the new platform-ws.ts so use-live-feed.ts needed no
changes). Both route through Tauri's Rust side instead of the webview's own
fetch/WebSocket. Capabilities scoped to 127.0.0.1:3000/localhost:3000, matching
the existing CSP allowlist.

apps/web/src/api.ts

@@ -6,7 +6,7 @@
 // wiki/entities/local-jwt-auth.md.
 
 import { logFailedRequest } from "./lib/logger.js";
-import { apiUrl } from "./lib/origin.js";
+import { apiUrl, platformFetch } from "./lib/origin.js";
 import type { AppLogRecord, ValidationLine, ValidationMode } from "@parking/shared";
 
 const CSRF_COOKIE = "parking_csrf";
@@ -28,7 +28,7 @@ export async function apiFetch<T>(path: string, init: RequestInit = {}): Promise
     const csrf = readCookie(CSRF_COOKIE);
     if (csrf) headers.set(CSRF_HEADER, csrf);
   }
-  const res = await fetch(apiUrl(path), { ...init, headers, credentials: "include" });
+  const res = await platformFetch(apiUrl(path), { ...init, headers, credentials: "include" });
   if (!res.ok) {
     const msg = (await res.json().catch(() => ({}))) as { error?: string; problems?: string[]; [k: string]: unknown };
     const error = msg.error ?? `${path}: ${res.status}`;

apps/web/src/lib/logger.ts

@@ -14,6 +14,7 @@
 //    high-signal sources (failed requests, uncaught errors) are always captured.
 
 import { LOG_LEVEL_ORDER, type ClientLogInput, type LogLevel } from "@parking/shared";
+import { apiUrl, platformFetch } from "./origin.js";
 
 const ENDPOINT = "/api/logs";
 const FLUSH_MS = 4000;
@@ -76,7 +77,7 @@ async function flush(): Promise<void> {
     const headers: Record<string, string> = { "content-type": "application/json" };
     const csrf = readCookie(CSRF_COOKIE);
     if (csrf) headers[CSRF_HEADER] = csrf;
-    await fetch(ENDPOINT, {
+    await platformFetch(apiUrl(ENDPOINT), {
       method: "POST",
       headers,
       credentials: "include",
@@ -90,7 +91,10 @@ async function flush(): Promise<void> {
   }
 }
 
-/** Best-effort synchronous flush on page hide (sendBeacon survives unload). */
+/** Best-effort synchronous flush on page hide (sendBeacon survives unload). Browser
+ *  only — sendBeacon is a native browser API with no Tauri-HTTP-plugin equivalent,
+ *  so this drops silently in the desktop shell (unload is rare there; the regular
+ *  4s-interval flush above covers the common case). */
 function flushBeacon(): void {
   if (queue.length === 0) return;
   const entries = queue.splice(0, queue.length);
@@ -99,7 +103,7 @@ function flushBeacon(): void {
     // sendBeacon can't set the CSRF header; the server accepts the ingest for any
     // signed-in session (cookie sent automatically). If CSRF later guards it strictly,
     // this path degrades to "lost on unload" — acceptable for diagnostics.
-    navigator.sendBeacon(ENDPOINT, blob);
+    navigator.sendBeacon(apiUrl(ENDPOINT), blob);
   } catch {
     /* ignore */
   }

apps/web/src/lib/origin.ts

@@ -10,6 +10,15 @@
 // Keep this the SINGLE source for the backend origin — api.ts and the live-feed
 // WebSocket both read it, so the web app and the desktop shell stay identical
 // except for this one build-time value.
+//
+// platformFetch(): WebKitGTK treats tauri://localhost as a SECURE origin, so a
+// plain http://127.0.0.1:3000 fetch() from inside it is blocked as mixed
+// content (a WebKit limitation — CSP's connect-src does NOT override this;
+// found 2026-09-03 as "Load failed" on every desktop request). Inside Tauri we
+// dynamically import @tauri-apps/plugin-http's fetch, which routes the request
+// through Tauri's native side instead of the webview's own fetch, sidestepping
+// the check entirely. Browser build never imports the plugin (dynamic import,
+// same pattern as desktop-updater.ts).
 
 /** Backend HTTP origin, no trailing slash. Empty string = same-origin/relative. */
 export const API_BASE: string = (import.meta.env.VITE_API_BASE ?? "").replace(/\/$/, "");
@@ -28,3 +37,22 @@ export function wsUrl(path: string): string {
   const proto = window.location.protocol === "https:" ? "wss:" : "ws:";
   return `${proto}//${window.location.host}${path}`;
 }
+
+/** True when running inside the Tauri webview (not a normal browser). */
+function inTauri(): boolean {
+  return typeof window !== "undefined" && "__TAURI_INTERNALS__" in window;
+}
+
+/**
+ * fetch(), but routed through @tauri-apps/plugin-http inside the desktop
+ * shell (see the file header for why the webview's own fetch can't reach
+ * the local backend). Same signature as the global fetch; a plain pass-
+ * through in the browser.
+ */
+export async function platformFetch(input: RequestInfo | URL, init?: RequestInit): Promise<Response> {
+  if (inTauri()) {
+    const { fetch: tauriFetch } = await import("@tauri-apps/plugin-http");
+    return tauriFetch(input, init);
+  }
+  return fetch(input, init);
+}

apps/web/src/lib/platform-ws.ts

@@ -0,0 +1,102 @@
+// Desktop-only WebSocket adapter.
+//
+// WebKitGTK treats tauri://localhost as a SECURE origin, so a plain
+// ws://127.0.0.1:3000 connection from inside it is blocked as mixed content —
+// same root cause as the HTTP fetch() issue (see origin.ts's platformFetch),
+// but WS is a separate browser check with its own plugin
+// (@tauri-apps/plugin-websocket), which routes the connection through Tauri's
+// native side instead of the webview's own WebSocket.
+//
+// That plugin's API is async/listener-based, not the synchronous
+// onopen/onmessage/onclose event surface use-live-feed.ts is written against
+// (and has already been hardened for — reconnect backoff, StrictMode
+// double-invoke, cleanup). Rather than rewrite that hook around a different
+// API shape, this adapter presents the same native-WebSocket-like interface
+// use-live-feed.ts already expects, so that hook needs no changes at all.
+//
+// Browser build: plain pass-through to the real WebSocket (this file's
+// createPlatformSocket is only called from inside inTauri() callers).
+
+export interface PlatformSocket {
+  onopen: (() => void) | null;
+  onmessage: ((ev: { data: string }) => void) | null;
+  onclose: (() => void) | null;
+  onerror: (() => void) | null;
+  close(): void;
+}
+
+class NativeSocketAdapter implements PlatformSocket {
+  onopen: (() => void) | null = null;
+  onmessage: ((ev: { data: string }) => void) | null = null;
+  onclose: (() => void) | null = null;
+  onerror: (() => void) | null = null;
+  #sock: WebSocket;
+
+  constructor(url: string) {
+    this.#sock = new WebSocket(url);
+    this.#sock.onopen = () => this.onopen?.();
+    this.#sock.onmessage = (ev) => this.onmessage?.({ data: ev.data as string });
+    this.#sock.onclose = () => this.onclose?.();
+    this.#sock.onerror = () => this.onerror?.();
+  }
+
+  close(): void {
+    this.#sock.close();
+  }
+}
+
+class TauriSocketAdapter implements PlatformSocket {
+  onopen: (() => void) | null = null;
+  onmessage: ((ev: { data: string }) => void) | null = null;
+  onclose: (() => void) | null = null;
+  onerror: (() => void) | null = null;
+  #closed = false;
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  #conn: any = null;
+
+  constructor(url: string) {
+    void this.#connect(url);
+  }
+
+  async #connect(url: string): Promise<void> {
+    try {
+      const { default: TauriWebSocket } = await import("@tauri-apps/plugin-websocket");
+      if (this.#closed) return; // close() called before connect resolved
+      const conn = await TauriWebSocket.connect(url);
+      if (this.#closed) {
+        void conn.disconnect();
+        return;
+      }
+      this.#conn = conn;
+      conn.addListener((msg: { type: string; data: unknown }) => {
+        if (msg.type === "Text") {
+          this.onmessage?.({ data: msg.data as string });
+        } else if (msg.type === "Close") {
+          this.onclose?.();
+        }
+        // Binary/Ping/Pong: the server protocol here is text-JSON only (see
+        // routes/ws.ts) — nothing else is expected.
+      });
+      this.onopen?.();
+    } catch {
+      this.onerror?.();
+      this.onclose?.();
+    }
+  }
+
+  close(): void {
+    this.#closed = true;
+    void this.#conn?.disconnect();
+  }
+}
+
+/** True when running inside the Tauri webview (not a normal browser). */
+function inTauri(): boolean {
+  return typeof window !== "undefined" && "__TAURI_INTERNALS__" in window;
+}
+
+/** Open a live-feed socket, routed through the Tauri WebSocket plugin inside the
+ *  desktop shell (mixed-content workaround), or the native WebSocket in a browser. */
+export function createPlatformSocket(url: string): PlatformSocket {
+  return inTauri() ? new TauriSocketAdapter(url) : new NativeSocketAdapter(url);
+}

apps/web/src/lib/use-live-feed.ts

@@ -4,6 +4,7 @@ import type { DeviceStatus, LedgerEvent, Occupancy } from "../api.js";
 import { qk } from "./query.js";
 import { useLiveStore, type LaneStatus, type LanePresence } from "./live-store.js";
 import { wsUrl } from "./origin.js";
+import { createPlatformSocket, type PlatformSocket } from "./platform-ws.js";
 
 // Booth WebSocket client. Opens ONE socket to /api/ws and turns server pushes into
 // (a) live-store updates for the ticker/occupancy and (b) Query cache invalidations
@@ -36,7 +37,7 @@ export function useLiveFeed(enabled: boolean = true): void {
     useLiveStore();
   // Hold the socket + reconnect timer across renders; guard against StrictMode
   // double-invoke and unmount.
-  const sockRef = useRef<WebSocket | null>(null);
+  const sockRef = useRef<PlatformSocket | null>(null);
   const retryRef = useRef(0);
   const closedRef = useRef(false);
 
@@ -50,7 +51,7 @@ export function useLiveFeed(enabled: boolean = true): void {
     const connect = () => {
       if (closedRef.current) return;
       setStatus(retryRef.current === 0 ? "connecting" : "connecting");
-      const sock = new WebSocket(wsUrl("/api/ws"));
+      const sock = createPlatformSocket(wsUrl("/api/ws"));
       sockRef.current = sock;
 
       sock.onopen = () => {