Merge develop into main (#313)

- Add app path get() functions to `TactilityC`
- Improved `Dispatcher` and `DispatcherThread`
- Improved `PubSub` (type safety)
- Created test for `DispatcherThread` and `PubSub`
- Save properties files on app exit (various apps) by posting it to the main dispatcher (fixes UI hanging briefly on app exit)
- Fixed bug with `SystemSettings` being read from the wrong file path.
- `loadPropertiesFile()` now uses `file::readLines()` instead of doing that manually
- Increased timer task stack size (required due to issues when reading a properties file for the very first time)
- General cleanup
- Created `EstimatedPower` driver that uses an ADC pin to measure voltage and estimate the battery charge that is left.
- Cleanup of T-Deck board (updated to new style)

TactilityC/Include/tt_app.h

@@ -7,6 +7,7 @@ extern "C" {
 #endif
 
 typedef void* AppHandle;
+typedef void* AppPathsHandle;
 
 /** @return the bundle that belongs to this application, or null if it wasn't started with parameters. */
 BundleHandle _Nullable tt_app_get_parameters(AppHandle handle);
@@ -14,7 +15,7 @@ BundleHandle _Nullable tt_app_get_parameters(AppHandle handle);
 /**
  * Set the result before closing an app.
  * The result and bundle are passed along to the app that launched this app, when this app is closed.
- * @param[in] handle the app context handle to set the result for
+ * @param[in] handle the app handle to set the result for
  * @param[in] result the result state to set
  * @param[in] bundle the result bundle to set
  */
@@ -23,6 +24,21 @@ void tt_app_set_result(AppHandle handle, AppResult result, BundleHandle _Nullabl
 /** @return true if a result was set for this app context */
 bool tt_app_has_result(AppHandle handle);
 
+/** Get the path to the data directory of this app.
+ * @param[in] handle the app handle
+ * @param[out] buffer the output buffer (recommended size is 256 bytes)
+ * @param[inout] size used as input for maximum buffer size (including null terminator) and is set with the path string length by this function
+ */
+void tt_app_get_data_directory(AppPathsHandle handle, char* buffer, size_t& size);
+
+/** Get the path to the data directory of this app, with LVGL drive letter prefix applied.
+ * The recommended buffer size is 256 bytes.
+ * @param[in] handle the app handle
+ * @param[out] buffer the output buffer (recommended size is 256 bytes)
+ * @param[inout] size used as input for maximum buffer size (including null terminator) and is set with the path string length by this function
+ */
+void tt_app_get_data_directory_lvgl(AppPathsHandle handle, char* buffer, size_t& size);
+
 /**
  * Start an app by id.
  * @param[in] appId the app manifest id