feat: enable public sharing in demo launch configuration

refactor: remove custom retry logic and progress tracking in favor of direct requests with status logging

feat: integrate Gradio Progress tracking into build_persona and add _safe_json utility for robust response parsing

feat: add JSON decoding robustness and interactive progress UI for memory generation

refactor: introduce modal_post and modal_get helpers with unified retry logic for handling cold starts

feat: enable public sharing for the demo interface in app.py

refactor: add safe_json helper and improve error handling for backend API calls

feat: implement Gradio-based Memory Keeper interface with multi-modal AI integration