BUG: Ceramic One daemon fails to start on testnet-clay due to an invalid default Ethereum RPC URL

**Describe the bug**
The Ceramic One daemon fails to start on testnet-clay due to an invalid default Ethereum RPC URL. The codebase uses `https://gnosis-mainnet.public.blastapi.io`, which is for Gnosis mainnet (not Chiado testnet) and has been deprecated by Blast API, resulting in a 403 error. This prevents the daemon from launching without manual RPC configuration.

**To Reproduce**
Steps to reproduce the behavior:
1. Set up Ceramic One via Docker Compose as per the docs (https://developers.ceramic.network/docs/protocol/ceramic-one/usage/installation#docker-compose).
2. Run `docker-compose up -d`.
3. Check container logs with `docker logs `.
4. See the error: "No usable ethereum RPC configured for network testnet-clay".

**Expected behavior**
The daemon should start successfully.

**Ceramic versions**
Ceramic One: 0.57.0 (build: git:0a7b433-modified)

**Machine, OS, browser information (please complete the following information):**
Linux 6.17.9-arch1-1

**Additional context**

Relevant logs:
```
2025-11-28T17:27:10.117903Z WARN ceramic_one: failed to create RPC client with url: 'https://gnosis-mainnet.public.blastapi.io': InvalidArgument("failed to retrieve chain ID: HTTP error 403 with body: {\n \"jsonrpc\": \"2.0\",\n \"id\": null,\n \"error\": {\n \"code\": -32000,\n \"message\": \"Blast API is no longer available. Please update your integration to use Alchemy's API instead: https://alchemy.com\"\n }\n}\n")
2025-11-28T17:27:10.117919Z ERROR ceramic_one: Error running command: No usable ethereum RPC configured for network testnet-clay
```