Merge develop into main (#327)

## New features
- Implemented support for app packaging in firmware and `tactility.py`: load `.app` files instead of `.elf` files. Install apps remotely or via `FileBrowser`.
- Ensure headless mode works: all services that require LVGL can deal with the absence of a display
- Service `onStart()` is now allowed to fail (return `bool` result)
- Added and improved various file-related helper functions

## Improvements
- Completely revamped the SystemInfo app UI
- Improved Calculator UI of internal and external variant
- Fix Chat UI and removed the emoji buttons for now
- Fix for toolbar bottom padding issue in all apps

## Fixes
- Fix for allowing recursive locking for certain SPI SD cards
& more

Tactility/Source/service/gui/GuiService.cpp

@@ -112,7 +112,13 @@ void GuiService::redraw() {
     unlock();
 }
 
-void GuiService::onStart(TT_UNUSED ServiceContext& service) {
+bool GuiService::onStart(TT_UNUSED ServiceContext& service) {
+    auto* screen_root = lv_screen_active();
+    if (screen_root == nullptr) {
+        TT_LOG_E(TAG, "No display found");
+        return false;
+    }
+
     thread = new Thread(
         "gui",
         4096, // Last known minimum was 2800 for launching desktop
@@ -123,12 +129,9 @@ void GuiService::onStart(TT_UNUSED ServiceContext& service) {
         onLoaderEvent(event);
     });
 
+    lvgl::lock(portMAX_DELAY);
 
-    tt_check(lvgl::lock(1000 / portTICK_PERIOD_MS));
     keyboardGroup = lv_group_create();
-    auto* screen_root = lv_screen_active();
-    assert(screen_root != nullptr);
-
     lvgl::obj_set_style_bg_blacken(screen_root);
 
     lv_obj_t* vertical_container = lv_obj_create(screen_root);
@@ -156,6 +159,8 @@ void GuiService::onStart(TT_UNUSED ServiceContext& service) {
 
     thread->setPriority(THREAD_PRIORITY_SERVICE);
     thread->start();
+
+    return true;
 }
 
 void GuiService::onStop(TT_UNUSED ServiceContext& service) {