Make agents less insistent on running `stash db push` when not using Proxy

[auxesis]

When running stash plan and stash impl, Claude can be quite insistent on running stash db push.

stash db push is only needed when users are also querying their data with CipherStash Proxy.

For users integrating CipherStash into their apps, the Encryption SDK defines the encryption configuration in the app — there is no encryption configuration stored in the database.

We need to reinforce with agents that running stash db push is not required unless the user has explicitly said they want to query their data via Proxy.