Add AI agent setup prompt, start.sh launcher, and container resource limits

Adds a copy-pasteable prompt for non-technical users to set up poke-mail
via their AI coding agent, a start.sh script that loads .env, activates
the virtualenv, starts the server, and tunnels to Poke, and recommended
container resource limits for orchestrators.

start.sh

@@ -0,0 +1,29 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cd "$(dirname "$0")"
+
+# Load .env if present
+if [ -f .env ]; then
+  set -a
+  source .env
+  set +a
+fi
+
+# Activate virtualenv
+source .venv/bin/activate
+
+: "${MCP_API_KEY:?MCP_API_KEY is not set — add it to .env or export it}"
+
+# Start poke-mail server in background
+echo "Starting poke-mail server..."
+python src/server.py &
+SERVER_PID=$!
+trap "kill $SERVER_PID 2>/dev/null" EXIT
+
+# Wait for server to be ready
+sleep 2
+
+# Tunnel to Poke
+echo "Starting tunnel to Poke..."
+poke tunnel http://localhost:3000/mcp --name "poke-mail"