Add main application logic and touch handling functionality

- Implemented main application entry point in main.cpp, initializing queues and event groups.
- Created TouchHandler and EInkTouchHandler classes for handling touch events.
- Added a minimal event loop for touch processing in touch.cpp.
- Introduced unit tests for the hello world application in pytest_hello_world.py.
- Added configuration files for CI and Wokwi support.
- Created empty header files for network and UI modules.

main/common/constants.h

@@ -0,0 +1,14 @@
+// 800x480 = 384,000 pixels
+
+#define EINK_WIDTH    800
+#define EINK_HEIGHT   480
+
+#define CORE_0 0
+#define CORE_1 1
+
+#define SYSTEM_SHUTDOWN_BIT     (1 << 0)
+#define SYSTEM_RESTART_BIT      (1 << 1)
+#define SYSTEM_START_BIT        (1 << 2)
+//
+#define DISPLAY_READY_BIT       (1 << 1)
+#define TOUCH_CALIBRATED_BIT    (1 << 2)

main/common/queue_defs.h

@@ -0,0 +1,30 @@
+#include <indev/lv_indev.h>
+
+typedef enum {
+  CMD_DISPLAY_UPDATE,
+  CMD_SAVE_DATA,
+  CMD_LOAD_DATA,
+  CMD_REFRESH_DISPLAY,
+  CMD_SYSTEM_STATUS,
+} cmd_type_t;
+
+typedef struct {
+  cmd_type_t type;
+  uint32_t id;
+  void* data;
+  size_t len;
+  QueueHandle_t reply_to;  // NULL if one-way
+} async_cmd_t;
+
+extern QueueHandle_t command_queue;
+
+typedef struct {
+  uint16_t x, y;
+  lv_indev_state_t state;  // LV_INDEV_STATE_PR/REL
+  uint32_t timestamp;
+  uint8_t gesture;         // TAP, SWIPE, LONG_PRESS
+} touch_event_t;
+
+extern QueueHandle_t touch_queue;
+
+extern EventGroupHandle_t system_event_group;