added pi zero backend for wrapping gpsd

pi/backend/main.py

@@ -0,0 +1,39 @@
+"""Smart Serow Backend - GPS service with HTTP API."""
+
+from flask import Flask, jsonify
+from gps_service import GPSService
+
+app = Flask(__name__)
+gps = GPSService()
+
+
+@app.route("/health")
+def health():
+    """Health check endpoint."""
+    return jsonify({"status": "ok", "gps_connected": gps.connected})
+
+
+@app.route("/gps")
+def gps_data():
+    """Current GPS data."""
+    return jsonify(gps.get_latest())
+
+
+@app.route("/gps/history")
+def gps_history():
+    """Buffered GPS history."""
+    return jsonify(gps.get_buffer())
+
+
+def main():
+    """Entry point."""
+    gps.start()
+    try:
+        # Host 0.0.0.0 for access from Flutter app
+        app.run(host="0.0.0.0", port=5000, debug=False)
+    finally:
+        gps.stop()
+
+
+if __name__ == "__main__":
+    main()