this should prepare us for backfill later and allow strongrefs etc bc thats just like. sane lol

also remove stupid car rev nonsense bc lowk was stupid lol

its only on startup the backfill overhead is NAWT that high (like one second to parse and save on my pc + only on startup its _nawt_ that bad. bottleneck is network atp)

optomizations to reduce downloaded car size (mst diffs) may be used later but i cba rn lol

i also need to figure out some rev logic to dedupe repo ops :3