refactor(ui): centralise EINK_DISPLAY_MODEL toggles in Features.h

Five sites in UITask.cpp + MyMesh.cpp branched on EINK_DISPLAY_MODEL
purely for runtime-shape decisions (blink rate, default pref values,
refresh intervals). Replace with a constexpr Features namespace:
IS_EINK, BLINK_INDICATORS, CLOCK_HIDE_SECONDS_DEFAULT, HOME_REFRESH_MS,
LOCKSCREEN_REFRESH_MS. Compiler dead-branch-eliminates so cost is
identical to the preprocessor branch, but the code stays reachable to
tooling and the policy lives in one file.

SettingsScreen and driver headers still need real #ifdef — they
condition enum members and class field layouts.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

examples/companion_radio/Features.h

@@ -0,0 +1,26 @@
+#pragma once
+
+// Build-time feature flags derived from board defines.
+// Use these instead of `#ifdef EINK_DISPLAY_MODEL` for runtime-shape decisions
+// (booleans, timings, defaults). Compiler dead-branch-eliminates on the
+// constexpr, so cost is identical to a preprocessor branch but the code
+// remains readable and reachable to tooling. Conditional struct members
+// (enum entries, NodePrefs fields) still need a real `#if defined(...)`.
+
+namespace Features {
+
+#if defined(EINK_DISPLAY_MODEL)
+  static constexpr bool     IS_EINK              = true;
+  static constexpr bool     BLINK_INDICATORS     = false;   // e-ink avoids high-rate redraws
+  static constexpr bool     CLOCK_HIDE_SECONDS_DEFAULT = true;  // pref starting value
+  static constexpr unsigned HOME_REFRESH_MS      = 30000;   // slow display polls less
+  static constexpr unsigned LOCKSCREEN_REFRESH_MS = 30000;
+#else
+  static constexpr bool     IS_EINK              = false;
+  static constexpr bool     BLINK_INDICATORS     = true;
+  static constexpr bool     CLOCK_HIDE_SECONDS_DEFAULT = false;
+  static constexpr unsigned HOME_REFRESH_MS      = 1000;
+  static constexpr unsigned LOCKSCREEN_REFRESH_MS = 1000;
+#endif
+
+} // namespace Features

examples/companion_radio/MyMesh.cpp

@@ -1,5 +1,6 @@
 #include "MyMesh.h"
 #include "MsgExpand.h"
+#include "Features.h"
 
 #include <Arduino.h> // needed for PlatformIO
 #include <Mesh.h>
@@ -952,9 +953,7 @@ MyMesh::MyMesh(mesh::Radio &radio, mesh::RNG &rng, mesh::RTCClock &rtc, SimpleMe
   _prefs.dm_show_all = 1;        // show all contacts by default
   memset(_prefs.dm_notif, 0, sizeof(_prefs.dm_notif));
   _prefs.auto_off_secs = 15;    // 15 seconds auto-off by default
-#ifdef EINK_DISPLAY_MODEL
-  _prefs.clock_hide_seconds = 1;  // e-ink: seconds cause a panel refresh every second
-#endif
+  _prefs.clock_hide_seconds = Features::CLOCK_HIDE_SECONDS_DEFAULT ? 1 : 0;
   _prefs.tz_offset_hours = 0;  // UTC by default
   _prefs.low_batt_mv = 3400;  // auto-shutdown at 3.4V by default
   _prefs.batt_display_mode = 0; // icon by default

examples/companion_radio/ui-new/UITask.cpp

@@ -2,6 +2,7 @@
 #include <helpers/TxtDataHelpers.h>
 #include "../MyMesh.h"
 #include "../MsgExpand.h"
+#include "../Features.h"
 #include "target.h"
 #ifdef WIFI_SSID
   #include <WiFi.h>
@@ -337,11 +338,7 @@ class HomeScreen : public UIScreen {
       // "A" indicator — left of BT; blinks on OLED, always shown on e-ink
       if (_node_prefs && _node_prefs->advert_auto_interval_sec > 0) {
         int aX = leftmostX - ind;
-#ifdef EINK_DISPLAY_MODEL
-        bool show_a = true;
-#else
-        bool show_a = (millis() % 4000) < 2000;
-#endif
+        bool show_a = Features::BLINK_INDICATORS ? ((millis() % 4000) < 2000) : true;
         if (show_a) {
           display.setColor(DisplayDriver::LIGHT);
           display.fillRect(aX, 0, ind, ind_h);
@@ -447,11 +444,7 @@ public:
         char buf[24];
         display.setColor(DisplayDriver::LIGHT);
         display.setTextSize(2);
-#ifdef EINK_DISPLAY_MODEL
-        bool show_sec = false;
-#else
-        bool show_sec = !_node_prefs || !_node_prefs->clock_hide_seconds;
-#endif
+        bool show_sec = !Features::IS_EINK && (!_node_prefs || !_node_prefs->clock_hide_seconds);
         bool h12 = _node_prefs && _node_prefs->clock_12h;
         if (h12) {
           int h = ti->tm_hour % 12; if (h == 0) h = 12;
@@ -774,16 +767,15 @@ public:
       }
     }
     bool auto_adv = _node_prefs && _node_prefs->advert_auto_interval_sec > 0;
-#ifdef EINK_DISPLAY_MODEL
-    if (_page == HomePage::CLOCK) return 30000;  // no seconds on e-ink; refresh every 30s
-    return 30000;  // e-ink: limit base polling; new messages still force immediate refresh via notify()
-#else
+    if (Features::IS_EINK) {
+      // slow display: poll every 30 s; inbound msgs force immediate refresh via notify()
+      return Features::HOME_REFRESH_MS;
+    }
     if (_page == HomePage::CLOCK) {
       bool show_sec = !_node_prefs || !_node_prefs->clock_hide_seconds;
       return auto_adv ? 1000 : (show_sec ? 1000 : 60000);
     }
     return auto_adv ? 1000 : 5000;
-#endif
   }
 
   bool handleInput(char c) override {
@@ -1478,11 +1470,7 @@ void UITask::loop() {
       _display->setCursor(hx, hy);
       _display->print(hint);
       _display->endFrame();
-#ifdef EINK_DISPLAY_MODEL
-      _next_refresh = millis() + 30000;
-#else
-      _next_refresh = millis() + 1000;
-#endif
+      _next_refresh = millis() + Features::LOCKSCREEN_REFRESH_MS;
     } else if (!_locked && millis() >= _next_refresh && curr) {
       _display->startFrame();
       int delay_millis = curr->render(*_display);