Android Social Networking App

I need an experienced mobile developer to create a social-networking app for Android from the ground up. The core idea is to let users connect, share posts, and message each other in real time, with a clean, modern interface that feels lightweight on lower-end devices.

Key functions I already know I want:
• Secure email or phone number sign-up / login
• Personal profiles with photo, bio, and basic stats
• Timeline where users can post text, images, and short videos
• Private one-to-one chat (push notifications included)
• Basic search to find and follow other users

You’re welcome to propose the tech stack you believe suits best—Kotlin with Jetpack components, Flutter, or a similar approach—as long as the final APK runs smoothly on current Android versions. Please outline:
1. Your suggested architecture (back-end, database, APIs).
2. Milestones that take the app from clickable prototype to Play Store-ready build.
3. Any past social or chat apps you’ve shipped.

Source code, concise documentation, and a brief handover call will complete the job. If anything above is unclear, feel free to ask; I reply quickly so we can get started without delay.