feat: add Hermes and GBrain host configs

Hermes: tool rewrites for terminal/read_file/patch/delegate_task,
paths to ~/.hermes/skills/gstack, AGENTS.md config file.

GBrain: coding skills become brain-aware when GBrain mod is installed.
Same tool rewrites as OpenClaw (agents spawn Claude Code via ACP).
GBRAIN_CONTEXT_LOAD and GBRAIN_SAVE_RESULTS NOT suppressed on gbrain
host, enabling brain-first lookup and save-to-brain behavior.

Both registered in hosts/index.ts with setup script redirect messages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

setup

@@ -67,7 +67,29 @@ case "$HOST" in
     echo "  3. See docs/OPENCLAW.md for the full architecture"
     echo ""
     exit 0 ;;
-  *) echo "Unknown --host value: $HOST (expected claude, codex, kiro, factory, openclaw, or auto)" >&2; exit 1 ;;
+  hermes)
+    echo ""
+    echo "Hermes integration uses the same model as OpenClaw — Hermes spawns"
+    echo "Claude Code sessions, and gstack provides methodology artifacts."
+    echo ""
+    echo "To integrate gstack with Hermes:"
+    echo "  1. Tell your Hermes agent: 'install gstack for hermes'"
+    echo "  2. Or generate artifacts: bun run gen:skill-docs --host hermes"
+    echo ""
+    exit 0 ;;
+  gbrain)
+    echo ""
+    echo "GBrain is a mod for gstack — it makes coding skills brain-aware."
+    echo "GBrain generates brain-enhanced skill variants that search your brain"
+    echo "for context before starting and save results after finishing."
+    echo ""
+    echo "To generate brain-aware skills:"
+    echo "  bun run gen:skill-docs --host gbrain"
+    echo ""
+    echo "GBrain setup and brain skills ship from the GBrain repo."
+    echo ""
+    exit 0 ;;
+  *) echo "Unknown --host value: $HOST (expected claude, codex, kiro, factory, openclaw, hermes, gbrain, or auto)" >&2; exit 1 ;;
 esac
 
 # ─── Resolve skill prefix preference ─────────────────────────