Wire Android SSO Custom Tabs, carousel-safe swipes, and core saveMedia.

Open SSO in Capacitor Browser with paarrot://android return; stop swipe-to-reply stealing carousel scrolls; bump cinny for shared save helpers and register MediaStore from the overlay.

overlay/src/app/utils/registerAndroidMediaSaver.ts

@@ -0,0 +1,67 @@
+import { Capacitor, registerPlugin } from '@capacitor/core';
+import { registerMediaSaver } from './saveMedia';
+
+interface AndroidShareHandlerSavePlugin {
+  saveFile(options: {
+    filename: string;
+    mimeType?: string;
+    base64: string;
+  }): Promise<{ saved: boolean; shared?: boolean; uri?: string }>;
+}
+
+const AndroidShareHandler = registerPlugin<AndroidShareHandlerSavePlugin>('AndroidShareHandler');
+
+const blobToBase64 = (blob: Blob): Promise<string> =>
+  new Promise((resolve, reject) => {
+    const reader = new FileReader();
+    reader.onload = () => {
+      const result = reader.result;
+      if (typeof result !== 'string') {
+        reject(new Error('Failed to read blob as base64'));
+        return;
+      }
+      resolve(result.includes(',') ? result.split(',')[1] : result);
+    };
+    reader.onerror = () => reject(reader.error ?? new Error('FileReader failed'));
+    reader.readAsDataURL(blob);
+  });
+
+const guessMimeFromName = (filename: string): string | undefined => {
+  const ext = filename.split('.').pop()?.toLowerCase();
+  if (!ext) return undefined;
+  const map: Record<string, string> = {
+    jpg: 'image/jpeg',
+    jpeg: 'image/jpeg',
+    png: 'image/png',
+    gif: 'image/gif',
+    webp: 'image/webp',
+    bmp: 'image/bmp',
+    svg: 'image/svg+xml',
+    mp4: 'video/mp4',
+    webm: 'video/webm',
+    mkv: 'video/x-matroska',
+    mov: 'video/quicktime',
+    mp3: 'audio/mpeg',
+    ogg: 'audio/ogg',
+    wav: 'audio/wav',
+    pdf: 'application/pdf',
+    txt: 'text/plain',
+  };
+  return map[ext];
+};
+
+/**
+ * Wire Capacitor Android MediaStore saves into the core saveMedia helpers.
+ * Call once at app startup from the mobile overlay entry.
+ */
+export function registerAndroidMediaSaver(): void {
+  if (!(Capacitor.isNativePlatform() && Capacitor.getPlatform() === 'android')) {
+    return;
+  }
+
+  registerMediaSaver(async (blob, filename) => {
+    const base64 = await blobToBase64(blob);
+    const mimeType = blob.type || guessMimeFromName(filename) || 'application/octet-stream';
+    await AndroidShareHandler.saveFile({ filename, mimeType, base64 });
+  });
+}