connect frontend to HF Space backend, fix CORS default

fix: drop conflicting version pins, let crewai drive dep resolution

fix: httpx~=0.28.1 to satisfy crewai==1.14.5 dependency constraint

fix: use python:3.11 full image — crewai deps need C build tools

fix: add HF Space README.md, remove stale backend files

fix: 5 bugs found in security and payment flow

feat: server-side payment enforcement with on-chain tx verification

fix: remove crewai-tools dep, rewrite Docs/Pricing for no-auth free tool

refactor: remove Supabase/auth/paywall — no DB needed

Initial commit — Squint screenshot-to-code app