fix: fleet config issues from 2026-07-18 relay review

- hermes-agent-baseline: add gpu-dense and gpu-light to models list
- hermes-config-template: fix pgrep traps (exclude infisical wrapper) + add
  vault empty-key guard documentation in Rule 13
- litellm-api-keys: fix pgrep pattern in auditable check
- scripts/agent-health-check: fix pgrep to exclude infisical bash wrapper

Addresses issues found during relay inbox resolution session:
1. pgrep -f 'hermes_cli.main gateway run' matches both the real python
   gateway and the infisical bash wrapper, causing false health readings
2. infisical vault stores empty key silently — no guard/monitoring
3. gpu-dense/gpu-light stable aliases missing from baseline config

hermes-config-template.prose.md

@@ -325,7 +325,8 @@ verify ALL FOUR of these against the live config. They are the only root causes
 
 One-line agent health check (run on the agent host):
 ```bash
-PID=$(pgrep -f "python -m hermes_cli.main gateway run" | head -1)
+# Use grep -v infisical to avoid matching the bash wrapper that contains the same string
+PID=$(pgrep -f "python -m hermes_cli.main gateway run" | grep -v infisical | head -1)
 cat /proc/$PID/environ | tr '\0' '\n' | grep ^LITELLM_API_KEY= | sed 's/=.*/<set>/'
 curl -s -o /dev/null -w 'key_health: %{http_code}\n' -H "Authorization: Bearer $(cat /proc/$PID/environ | tr '\0' '\n' | grep ^LITELLM_API_KEY= | cut -d= -f2)" http://192.168.68.116/v1/models
 ```
@@ -351,9 +352,19 @@ directly (no infisical). Apply with `systemctl daemon-reload && systemctl restar
 The wrapper sources `~/.hermes/.env` then exports `LITELLM_API_KEY="$<AGENT>_LITELLM_API_KEY"`.
 See litellm-api-keys.prose.md § Machine Identity for Vault Writes for vault sync.
 
+**⚠️ Vault empty-key guard:** If the vault stores the secret as an empty string,
+the wrapper will inject an empty key and the gateway will silently get 401 errors
+on all LiteLLM requests (triggering silent DeepSeek fallback). The `.env` fallback
+is present but the vault takes precedence when the secret key exists (even if empty).
+
+**Fix:** The wrapper MUST validate the key length after injection. If LITELLM_API_KEY
+is empty or shorter than 20 chars, log a warning and either fail with a clear error
+message or fall back to the `.env` value before starting the gateway.
+
 **Verification (all agents):**
 ```bash
-GP=$(pgrep -f "python -m hermes_cli.main gateway run" | head -1)
+# Use grep -v infisical to avoid matching the bash wrapper that contains the same string
+GP=$(pgrep -f "python -m hermes_cli.main gateway run" | grep -v infisical | head -1)
 K=$(cat /proc/$GP/environ | tr '\0' '\n' | grep '^LITELLM_API_KEY=' | cut -d= -f2)
 curl -s -o /dev/null -w '%{http_code}' -H "Authorization: Bearer $K" http://192.168.68.116/v1/models  # must be 200
 ```