feat(reticulum): complete messaging, calls, and P4 support

Add official Sideband/LXST messaging and telephony flows, realtime resource ownership, call and ping UI, durable unread state, and bounded Nomad/Micron browsing.

Integrate ESP32-P4/C6 gateway transport, TinyUSB CDC, ES8311 audio, shared Codec2 call media, Reticulum defaults, compatibility settings, and conformance coverage.

modules/ui_shared/include/ui/widgets/foreground_operation_overlay.h

@@ -12,6 +12,7 @@ enum class Slot : std::uint8_t
     I18nFontLoad,
     RouteImage,
     SettingsAction,
+    ReticulumPing,
     Count,
 };
 

modules/ui_shared/include/ui/widgets/reticulum_ping_overlay.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include "chat/domain/reticulum_identity.h"
+
+#include <cstdint>
+
+namespace ui::widgets::reticulum_ping
+{
+
+void show_loading(
+    const std::uint8_t destination_hash[::chat::kReticulumPeerHashSize],
+    const char* display_name);
+void show_send_failure(const char* detail);
+void show_delivered(
+    const std::uint8_t destination_hash[::chat::kReticulumPeerHashSize],
+    std::uint32_t latency_ms,
+    std::uint8_t hops);
+void show_timeout(
+    const std::uint8_t destination_hash[::chat::kReticulumPeerHashSize],
+    std::uint32_t elapsed_ms);
+void dismiss();
+bool active_for(
+    const std::uint8_t destination_hash[::chat::kReticulumPeerHashSize]);
+
+} // namespace ui::widgets::reticulum_ping