refactor: common split
fix: fmt
fix: fmt
chore(nix): update `flake.lock`
chore(gateway): prefix env. overrides with `BLOCKFROST_GATEWAY`
fix(node): log tx submission failures as warnings
This looks better in `journal`, IMO. Previously, we logged `http/400` as a yellow `tracing::warn!`, but its reason – the actual tx submit failure – as a white `tracing::info!`, which feels a little inconsistent.
We don’t use them (yet?) in the Platform, and working definitions are always available in `blockfrost-ops`, who _do_ use them.
Names like `SERVER_URL` are pretty generic – let’s prevent accidental clashes from inherited env. The new deployment at <https://icebreakers.mainnet.core.blockfrost.io/> is not using them, so we’re safe to do it.
docs: fix search and version