feat: expand companion platform, device controls, and memoir workflows

Add customer and operator login, BLE provisioning, device fleet controls, call memory, memoir generation, and refreshed family and maintenance portals. Include API contracts, migrations, firmware sources, tests, assets, and deployment documentation.

firmware/echoear-platform-agent/main/device_power.h

@@ -0,0 +1,8 @@
+#pragma once
+#include "esp_err.h"
+#include "cJSON.h"
+#include <stdbool.h>
+// Restore the microphone/call gate before audio initialization.
+esp_err_t device_power_boot(void);
+esp_err_t device_power_apply(const char *mode, bool maintenance_held);
+cJSON *device_power_report(void);