~x-ai/grok-latest → A (3:1)

A introduces a durable browse URL scheme (`/~/*` routes, `ItemId::browse_href`/`from_browse_uri` with normalization and tests) and deletes the entire theme subsystem (cookies, `/theme` handler, dual CSS, controls UI), replacing brittle `/?item=` redirects. B only swaps `Deque`/`VecDeque` recent-votes for append-only `List`/`Vec` with read-time capping and drops write-time trim—useful internal simplification, but narrower and leaves on-disk growth unbounded.