feat(ift): EventHub AI Router stack for Zed

FastAPI gateway with A/B/C lane orchestration, LiteLLM proxy config,
Swarm stack (postgres, redis, VPN off-by-default), deploy/smoke/audit scripts.

scripts/litellm-entrypoint.sh

@@ -0,0 +1,31 @@
+#!/bin/sh
+# Load Swarm secrets into env and start LiteLLM proxy
+set -eu
+
+read_secret() {
+  if [ -f "$1" ]; then
+    tr -d '\n\r' < "$1"
+  fi
+}
+
+if [ -f /run/secrets/novita_api_key ]; then
+  export NOVITA_API_KEY="$(read_secret /run/secrets/novita_api_key)"
+fi
+if [ -f /run/secrets/litellm_master_key ]; then
+  export LITELLM_MASTER_KEY="$(read_secret /run/secrets/litellm_master_key)"
+fi
+if [ -f /run/secrets/litellm_salt_key ]; then
+  export LITELLM_SALT_KEY="$(read_secret /run/secrets/litellm_salt_key)"
+fi
+if [ -f /run/secrets/groq_api_key ]; then
+  export GROQ_API_KEY="$(read_secret /run/secrets/groq_api_key)"
+fi
+if [ -f /run/secrets/gemini_api_key ]; then
+  export GEMINI_API_KEY="$(read_secret /run/secrets/gemini_api_key)"
+fi
+if [ -f /run/secrets/postgres_password ]; then
+  export POSTGRES_PASSWORD="$(read_secret /run/secrets/postgres_password)"
+  export DATABASE_URL="postgresql://${POSTGRES_USER:-litellm}:${POSTGRES_PASSWORD}@postgres:5432/${POSTGRES_DB:-litellm}"
+fi
+
+exec litellm --config /app/config.yaml --port 4000 --num_workers 2 "$@"