Add a reproducible script to build wasm, deploy core + monitor (+ mock) to testnet, initialize them, and write the resulting IDs into a committed `deployments/testnet.json` and the frontend `.env.example`.
Acceptance criteria
- One command deploys + initializes on testnet.
- Resulting contract IDs documented for contributors.
Add a reproducible script to build wasm, deploy core + monitor (+ mock) to testnet, initialize them, and write the resulting IDs into a committed `deployments/testnet.json` and the frontend `.env.example`.
Acceptance criteria