Bug fix + fixed a couple rendering issues

feat: SSE keepalive, reconnection, and is_processing flag

replace websocket transport with SSE

fix: buffer websocket events during disconnects and replay on reconnect

fix: simplify onboarding to join-then-oauth flow

feat: cleanup sandbox spaces on session end and increase cookie TTL

feat: require org membership to create sessions

feat: update models to MiniMax M2.5 (fireworks-ai) and Opus 4.6

feat: cooperative cancellation, session persistence, background generation

feat: merge HF Space improvements

functioning frontend and docker

Fix imports and add frontend to gitignore

formatting

Add web frontend infrastructure for HF Agent