terra: remove Hermes Agent

Consolidating on jupiter's isolated instance (hosts/jupiter/hermes-agent.nix)
instead of running a second one here. Drops the module import, its
opencode_go_api_key/telegram_bot_token secrets, and the now-stale
cross-reference in ollama's context_length comment.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

services/desktop/hermes-agent.nix

@@ -1,36 +0,0 @@
-{ ... }:
-
-# Hermes Agent (https://github.com/NousResearch/hermes-agent) — Nous
-# Research's tool-calling CLI/gateway agent, pointed at the local ollama
-# server (see hosts/terra/configuration.nix) over its OpenAI-compatible /v1
-# route instead of a cloud provider. The nixosModules.default this pulls in
-# comes from the hermes-agent flake input itself (flake.nix), not from
-# nixpkgs — it builds the agent from source via uv2nix, so there's no
-# curl-|-bash installer or runtime pip/npm involved.
-#
-# Native mode (container.enable stays false): a hardened systemd service is
-# enough here since the agent only needs to reach loopback ollama, and it
-# avoids the podman-rootful-needs-passwordless-sudo dance the module's docs
-# call out for container mode. addToSystemPackages puts `hermes` on darman's
-# PATH sharing state (sessions, memories, cron) with the service instead of
-# starting a second, disconnected ~/.hermes.
-{
-  services.hermes-agent = {
-    enable = true;
-    addToSystemPackages = true;
-
-    settings.model = {
-      provider = "custom";
-      base_url = "http://127.0.0.1:11434/v1";
-      # gemma4:12b, not qwen3.6:35b-a3b: same daily-driver model already
-      # loaded for librechat (services/desktop/librechat.nix) — reusing it
-      # means no second model has to swap into the 6800 XT's 16G VRAM
-      # alongside whatever's already resident.
-      default = "gemma4:12b";
-      # No api_key — ollama's OpenAI-compat endpoint doesn't check one.
-      # Mirrors OLLAMA_CONTEXT_LENGTH set on the ollama service itself;
-      # this is a client-side hint only, ollama enforces the real limit.
-      context_length = 131072;
-    };
-  };
-}