add files

ZoneManager.h

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+// =====================================================================
+// ZoneManager.h
+//
+// Rectangular detection-zone logic, ported from the ESP32-LD2450
+// project's main_zone.cpp. Works entirely on RadarTarget X/Y values,
+// so it is unaffected by however LD2453Parser ends up decoding raw
+// frames — nothing here needs to change once the parser is confirmed.
+// =====================================================================
+#pragma once
+
+#include <Arduino.h>
+#include "LD2453Parser.h"
+
+static const uint8_t MAX_ZONES = 3;
+
+struct Zone {
+    int x1, y1, x2, y2; // millimeters, same coordinate system as RadarTarget
+};
+
+class ZoneManager {
+public:
+    ZoneManager();
+
+    // Re-evaluate occupancy for all zones against the targets in
+    // `frame`. Call this once per new radar frame.
+    void update(const RadarFrame &frame);
+
+    bool isZoneOccupied(uint8_t zoneIndex) const;
+    Zone getZone(uint8_t zoneIndex) const;
+    void setZone(uint8_t zoneIndex, const Zone &zone);
+
+    // Serialize current zone definitions to JSON, e.g. for GET /zones.
+    // Returns the JSON string.
+    String zonesToJson() const;
+
+    // Parse a JSON body (as sent by POST /updateZones) and update
+    // zones in place. Missing fields keep their previous value.
+    // Returns false on JSON parse failure.
+    bool zonesFromJson(const uint8_t *data, size_t len);
+
+private:
+    Zone _zones[MAX_ZONES];
+    bool _occupied[MAX_ZONES];
+
+    static bool pointInZone(int x, int y, const Zone &z);
+};