fix bee chain config — use BEE_BLOCKCHAIN_RPC_ENDPOINT

Bee 2.x renamed BEE_SWAP_ENDPOINT to BEE_BLOCKCHAIN_RPC_ENDPOINT. With
the old name, Bee silently disables the chain backend and shuts down
with `factory fail: chain disabled`. Wire the endpoint inline so it
doesn't depend on the host .env.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

hostinger/prod-stack.yaml

@@ -159,6 +159,7 @@ services:
       BEE_P2P_ADDR: ":1634"
       BEE_VERBOSITY: "info"
       BEE_FULL_NODE: "false"
+      BEE_BLOCKCHAIN_RPC_ENDPOINT: "https://rpc.gnosischain.com"
       BEE_SWAP_ENABLE: "true"
       BEE_CHAIN_ENABLE: "true"
       BEE_NETWORK_ID: "1"