basic of display management. Backend to register and give image for the device. front end to manage displays etc.

Provider/main/api/devices/store.cpp

@@ -0,0 +1,57 @@
+// Device data store: CRUD helpers
+
+#include "device.hpp"
+
+// Find a device by MAC address, returns nullptr if not found
+internal device_t *find_device(const char *mac)
+{
+  for (int i = 0; i < MAX_DEVICES; i++)
+  {
+    if (g_Devices[i].active && strcmp(g_Devices[i].mac, mac) == 0)
+    {
+      return &g_Devices[i];
+    }
+  }
+  return nullptr;
+}
+
+// Register a device by MAC. Returns pointer to device (existing or new).
+// Sets *was_new to true if it was freshly registered.
+internal device_t *register_device(const char *mac, bool *was_new)
+{
+  *was_new = false;
+
+  // Check for existing
+  device_t *existing = find_device(mac);
+  if (existing)
+  {
+    return existing;
+  }
+
+  // Find a free slot
+  for (int i = 0; i < MAX_DEVICES; i++)
+  {
+    if (!g_Devices[i].active)
+    {
+      strlcpy(g_Devices[i].mac, mac, sizeof(g_Devices[i].mac));
+      g_Devices[i].active = true;
+      g_Devices[i].xml_layout[0] = '\0';
+      *was_new = true;
+      return &g_Devices[i];
+    }
+  }
+
+  return nullptr; // All slots full
+}
+
+// Update the XML layout for a device. Returns true on success.
+internal bool update_device_layout(const char *mac, const char *xml)
+{
+  device_t *dev = find_device(mac);
+  if (!dev)
+  {
+    return false;
+  }
+  strlcpy(dev->xml_layout, xml, sizeof(dev->xml_layout));
+  return true;
+}