saas: new tier policy

fix: timeout respect

fix: remove invalid cache lru

saas: use alternative endpoint for auth

fix: except 401 from uc authorization endpoint

feat: serp endpoint (#1180)

fix: user cache age comparison

fix: add jitter to user cache

fix: bring back content based respond timing

improve: cache usage and detection of js-required pages

fix: track if snapshot html modified by js

fix: tweak default timing to be more conservative

fix: custom script may listen to mutationIdle

behavior change: ditch content based return timing, adopt mutationIdle as default timing

docs: mention about discarded

feat: provide option to discard links

fix: a small lru for invalid tokens

feat: pdf upload and ip check

fix: robots-txt not loaded error conditions

docs: minor fix

docs: be neutral on brand

feat: md options pass though to turndown

fix: catch jsdom errors

restructure: nolonger a firebase application (#1160)