Two small follow-ups after the modelPrices PR (#1442):
- nix/modules/hive-c0re.nix: the `modelPrices` option `example` still
showed the old 5-minute sonnet `cache_write = 3.75`; the default is now
the 1-hour TTL `6.0`. Bump the example to match so it doesn't mislead.
- frontend/packages/agent/agent.css: remove the dead `.stats-empty-note`
selector (no element uses it — the stats empty state paints on canvas).
bd0b3efd8f