docs: replace invalid config get examples

[cosmopolitan033]

Problem

Three docs pages referenced hermes config get <key>, but hermes config does not provide a get subcommand. Following those snippets leads to an argparse error.

Solution

Replace the invalid per-key examples with hermes config show, and adjust the surrounding prose to tell readers which section/key to inspect in the resolved config.

Validation

$ rg "hermes config get" website/docs
# no matches

$ $HOME/.hermes/hermes-agent/venv/bin/python -m hermes_cli.main config show --help
usage: hermes config show [-h]

Confidence

Score: 88/100
Category: docs

Closes #30195