Add PG_CONN_STR to .env.example for host-side PostgreSQL connection

.env.example

@@ -19,6 +19,11 @@ AGENT_PRIVATE_KEY=
 # Optional: CoinGecko API key to reduce rate limits for market cap fetches
 COINGECKO_API_KEY=
 
+# PostgreSQL connection string (for host-side scripts: indicators, strategies)
+# When running in Docker, this is set in .env.docker
+# Example: PG_CONN_STR=postgresql://hyper:your_password@localhost:5432/hyper
+PG_CONN_STR=
+
 # Optional: Set a custom environment for development/testing
 # E.g., DEBUG=true
 DEBUG=