CI for OTA update

src/config.h

@@ -2,11 +2,14 @@
 #include <Arduino.h>
 
 namespace Config {
-// Updated by Karl on every version release (see
-    // CLAUDE.md workflow "Standard Workflow: Push & Release") - shown
-    // in the info screen (Menu > System > Info) and must match the
-    // corresponding Git tag.
-    constexpr const char* APP_VERSION = "3.6.3";
+// Updated by CI on every version release (see
+    // .gitea/workflows/release.yml) - shown in the info screen
+    // (Menu > System > Info). Locally built firmware shows "custom".
+#ifdef CI_VERSION
+    constexpr const char* APP_VERSION = CI_VERSION;
+#else
+    constexpr const char* APP_VERSION = "custom";
+#endif
 
 // Display brightness (Menu > System > Brightness), in percent.
     // MIN intentionally not 0 - a completely dark display could otherwise