feat(terraform): align partner testnet env contract

[auto-mausx]

Summary

• align terraform/partner-testnet with the current testnet env contract used in sig-kustomize
• replace the legacy single Solana RPC secret with split HTTP and WS secret inputs
• add Hydration env inputs to the partner testnet Terraform model
• update the example testnet tfvars accordingly

Why

The current partner-testnet Terraform shape is behind what testnet nodes are already using. This ports the relevant env/secret contract updates without changing the intended raw IP + port testnet deployment model.

Changes

• add sol_rpc_http_url_secret_id and sol_rpc_ws_url_secret_id
• add hydration_rpc_ws_url and hydration_signer_uri
• update main.tf env wiring to emit:
  • MPC_SOL_RPC_HTTP_URL
  • MPC_SOL_RPC_WS_URL
  • MPC_HYDRATION_RPC_WS_URL
  • MPC_HYDRATION_SIGNER_URI
• update the example tfvars to match

Notes

• intentionally preserves the existing testnet raw IP/port model for MPC_LOCAL_ADDRESS
• does not include any wrapper/CLI work