Fix Watcher permission review escalation failures

This patch fixes failed permission reviews caused by the Gateway model selection in 0.30.0.

What's new?

The Gateway monitor's default model is corrected to anthropic/claude-opus-4-7, restoring reviews of escalated permission requests.
The self-hosting documentation names the corrected model.
Server-managed monitoring and the configuration changes introduced in 0.30.0 remain in place.

When moving from 0.29.x or earlier, also follow the 0.30.0 upgrade steps. They still apply when you skip 0.30.0.

Install the current client for Apollo's hosted cloud.

curl -fsSL https://github.com/ApolloResearch/watcher-bin/releases/latest/download/install.sh | bash -s -- --cloud

Open a new terminal, then run:

watcher

Already installed? Follow the update guide. The installer refuses an existing installation.