Node does not clearly log selected network on startup

[strider-update]

Overview

When starting base/node, the logs do not clearly state which network configuration (e.g. Base Mainnet or Base Sepolia) is being used. This can make it harder for operators to confirm that the node is running against the intended network.

Problem Description

Node operators often run multiple environments (mainnet, testnet) and rely on startup logs to verify configuration. Currently, determining the active network may require inspecting environment files or digging through configuration values, which is error-prone.

Expected Behavior

• On startup, the node should explicitly log the selected network.
• The log should appear early and be easy to spot.
• Operators should be able to confirm network selection without inspecting config files.

Steps to Reproduce

1. Configure base/node with a specific .env file (e.g. .env.mainnet or .env.sepolia).
2. Start the node using Docker Compose.
3. Review startup logs.
4. Observe that the active network is not clearly logged.

Example

```bash
docker compose up
# Logs do not clearly indicate which network is active

Proposed Solution

• Add a clear, explicit startup log line that states the selected network.
• Include both the human-readable network name (e.g. Base Mainnet, Base Sepolia) and the chain ID.
• Emit the log early in the startup process, before dependent services begin initialization.

Acceptance Criteria

• Startup logs always display the active network and chain ID.
• The log is easy to identify without scanning verbose output.
• Behavior is consistent across all supported Base node networks.
• No functional changes beyond improved logging.