Android v1.3.1: Reliable Google Sign-In, Deep-Link Handoff & Browser Fallback

• 🔐 Android Credential Manager Activity Context Fix: Passed the host ComponentActivity directly to CredentialManager.getCredential instead of a MutableContextWrapper or AlertDialog ContextThemeWrapper, resolving silent bottom-sheet failures.
• 🌐 Seamless Browser OAuth Fallback for Sideloaded APKs: Detected GetCredentialCustomException OAuth/SHA-1 configuration errors (28444 / DEVELOPER_ERROR) and added automatic + 1-tap browser Google Sign-In handoff (/auth/mobile?fresh=1).
• 🔁 Eliminated Deep-Link & Auto-Prompt Loops: Consumed and cleared webnerdai://auth/callback Intent URIs immediately on receipt, guarded auto bottom-sheet prompts against window-resize recompositions, and replaced blind localStorage auto-redirects on /auth/mobile with verified /api/auth/me session checks and Android intent:// handoff.
• ⚡ Static Asset Routing & Stream Sync Fixes: Resolved /static/mobile-auth.js 404s in _serve_static, verified deep-link tokens against /api/auth/me, and aligned /api/articles stream query parameters.