fix(pwa): keep mobile OAuth consent from being swallowed by the installed app (#701)

## Problem

On mobile, starting an OAuth connection from ChatGPT (MCP connector)
opens the **installed Whisper Money PWA** and lands on the **dashboard**
instead of the OAuth consent screen — so the connection can never be
approved.

## Cause

The web app manifest declares `scope: "/"`, so the installed PWA claims
the entire origin, including `/oauth/authorize`. On Android the OAuth
link gets captured into the app, and the default launch behavior just
**focuses the already-open window (the dashboard) and drops the incoming
URL** — the consent page never loads.

Narrowing `scope` to exclude `/oauth` isn't viable: the app's routes are
flat (`/dashboard`, `/transactions`, `/accounts`, …) and share no
prefix, so a narrower scope would push half the app out to the browser.

## Fix

- `site.webmanifest`: add `launch_handler.client_mode: "focus-existing"`
so the launcher hands the app the captured target URL via the launch
queue.
- `app.tsx`: a `launchQueue` consumer that navigates to the target URL
when it's an `/oauth/` path. Every other launch is a no-op (keeps its
place).

Low blast radius — additive manifest field + a guard scoped to `/oauth/`
paths; existing (desktop) OAuth is unaffected.

## Verification

Cannot be tested off-device. After deploy, on the phone:
1. **Reinstall the PWA** (remove from home screen, re-add) so Android
re-fetches the manifest.
2. Retry the ChatGPT OAuth connect → should land on the "Connect ChatGPT
to Whisper Money" consent screen.

Depends on `launch_handler`/`launchQueue` (Chrome/Edge 102+, covers
nearly all Android).

public/favicon/site.webmanifest

@@ -6,6 +6,9 @@
   "scope": "/",
   "id": "/",
   "display": "standalone",
+  "launch_handler": {
+    "client_mode": "focus-existing"
+  },
   "orientation": "portrait-primary",
   "theme_color": "#1b1b18",
   "background_color": "#ffffff",

resources/js/app.tsx

@@ -34,6 +34,38 @@ import { __, setTranslations } from './utils/i18n';
 
 installChunkLoadRecovery();
 
+// The installed PWA claims the whole origin (manifest scope "/"), so on mobile an
+// OAuth link (e.g. from ChatGPT connecting over MCP) gets captured into the app.
+// Paired with launch_handler "focus-existing", the launcher hands us the target
+// URL instead of dropping it and showing the dashboard — navigate there so the
+// OAuth consent screen actually loads. Non-OAuth launches keep their place.
+type LaunchParams = { targetURL?: string };
+
+const launchQueue = (
+    window as Window & {
+        launchQueue?: {
+            setConsumer(consumer: (params: LaunchParams) => void): void;
+        };
+    }
+).launchQueue;
+
+if (launchQueue) {
+    launchQueue.setConsumer(({ targetURL }) => {
+        if (!targetURL) {
+            return;
+        }
+
+        const target = new URL(targetURL);
+
+        if (
+            target.pathname.startsWith('/oauth/') &&
+            target.href !== window.location.href
+        ) {
+            window.location.href = targetURL;
+        }
+    });
+}
+
 Sentry.init({
     dsn: import.meta.env.SENTRY_LARAVEL_DSN,
     environment: import.meta.env.MODE,