chore: remove unused import of netContext from env.ts

eslint flagged netContext as imported but never used (pre-existing).
Removing the unused import so the repo's eslint gate passes on the
modified area.

src/env.ts

@@ -1,7 +1,6 @@
 import 'dotenv/config'
 import { always } from '@welshman/lib'
 import { normalizeRelayUrl } from '@welshman/util'
-import { netContext } from '@welshman/net'
 import { Nip01Signer } from '@welshman/signer'
 import { routerContext } from '@welshman/router'