Fix module _ready flag and add license-headers CI job

.github/workflows/ci.yml

@@ -247,4 +247,4 @@ jobs:
             echo "::error::$missing file(s) missing the GPL-3.0 copyright header."
             exit 1
           fi
-          echo "All files have correct copyright headers."
+          echo "All files have correct copyright headers."

firmware/src/transmitter/modules/IModule.h

@@ -66,6 +66,11 @@ class IModule {
         return _ready;
     }
 
+    /// Mark the module as ready (called by ModuleManager after begin()).
+    void setReady() {
+        _ready = true;
+    }
+
     /// Slot index this module occupies (0-based).
     uint8_t slot() const {
         return _slot;

firmware/src/transmitter/modules/ModuleManager.cpp

@@ -50,6 +50,7 @@ void ModuleManager::scanAndInit() {
 
         auto mod = detectModule(slot);
         if (mod && mod->begin()) {
+            mod->setReady();
             _modules[slot] = std::move(mod);
         }
         _backplane.deselectAll();