Refactor Reticulum runtime ownership boundaries

Add Reticulum runtime budget, announce scheduling, deferred discovery, RX telemetry, and adapter scratch owners.

Route notification feedback through a platform notification runtime, keep product calls on Sideband LXST, and classify Reticulum network projections.

Unify LoRa TX budget handling across protocol actions, ACK retry, app sends, and MQTT downlink relay; document frozen runtime ownership rules and add smoke coverage.

modules/ui_shared/tests/test_chat_presentation_source.cpp

@@ -312,9 +312,10 @@ class PagingStore final : public ::chat::IChatStore
         return {meta};
     }
 
-    void setUnread(const ::chat::ConversationId&, int unread) override
+    bool setUnread(const ::chat::ConversationId&, int unread) override
     {
         unread_ = unread;
+        return true;
     }
 
     int getUnread(const ::chat::ConversationId&) const override