feat(lite): add ObsidianDragonLite build mode and gate full-node features

Add --lite build flow and ObsidianDragonLite target naming, hide full-node pages/features in lite mode, enforce pool-only mining in lite, and include chat port feasibility audit documentation.

src/app.h

@@ -130,6 +130,8 @@ public:
      * @brief Whether we are in the shutdown phase
      */
     bool isShuttingDown() const { return shutting_down_; }
+    bool isLiteBuild() const { return DRAGONX_LITE_BUILD != 0; }
+    bool supportsEmbeddedDaemon() const { return DRAGONX_ENABLE_EMBEDDED_DAEMON != 0; }
 
     /**
      * @brief Render the shutdown overlay (called instead of normal UI during shutdown)
@@ -439,7 +441,7 @@ private:
     bool show_address_book_ = false;
     
     // Embedded daemon state
-    bool use_embedded_daemon_ = true;
+    bool use_embedded_daemon_ = (DRAGONX_ENABLE_EMBEDDED_DAEMON != 0);
     std::string daemon_status_;
     mutable std::string daemon_mem_diag_;  // diagnostic info for daemon memory detection
     size_t daemon_output_offset_ = 0;      // for incremental output parsing (rescan detection)