feat: wizard config volume integration

- entrypoint.sh: wait for config file before starting uvicorn
- config.py: resolve DB URL from wizard config volume
- init_wizard.py: read config from file instead of HTTP
- Dockerfile: use entrypoint.sh

entrypoint.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+# Wait for wizard config before starting uvicorn
+CONFIG_DIR="${CONFIG_DIR:-/config}"
+CONFIG_FILE="${CONFIG_FILE:-harborforge.json}"
+CONFIG_PATH="$CONFIG_DIR/$CONFIG_FILE"
+
+echo "HarborForge Backend - waiting for config..."
+echo "  Config path: $CONFIG_PATH"
+
+while true; do
+  if [ -f "$CONFIG_PATH" ]; then
+    echo "  Config found! Starting backend..."
+    break
+  fi
+  echo "  Config not ready, waiting 5s... (run setup wizard via SSH tunnel)"
+  sleep 5
+done
+
+exec uvicorn app.main:app --host 0.0.0.0 --port 8000