fix: isolate Storage on its own httpx client (root cause of 404 storm)

fix: disable HTTP/1.1 keep-alive to stop Supabase gateway misrouting

fix: retry transient PostgREST schema-cache 404s; make history prep non-fatal

fix: pin supabase==2.22.0 (exact) and log actual installed version

fix: pin supabase>=2.15 for httpx_client ClientOptions support

fix: centralize Supabase client on HTTP/1.1 to stop RemoteProtocolError 500s