f0rmz: new subproject to create a form/wizard setup thing

shared/header.h

@@ -0,0 +1,60 @@
+/**
+ * Copyright 2025 buffybox contributors
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#ifndef BBX_HEADER_H
+#define BBX_HEADER_H
+
+#include "lvgl/lvgl.h"
+#include <stdbool.h>
+
+/**
+ * Header configuration options
+ */
+typedef struct {
+    /* Which elements to include */
+    bool show_theme_toggle;
+    bool show_keyboard_toggle;
+    bool show_layout_dropdown;
+    bool show_shutdown_button;
+
+    /* Dropdown options (if enabled) */
+    const char *dropdown_options;
+    int dropdown_width;
+
+    /* Button symbols */
+    const char *theme_symbol;
+    const char *keyboard_symbol;
+    const char *shutdown_symbol;
+} bbx_header_config_t;
+
+/**
+ * Header widget references for attaching callbacks
+ */
+typedef struct {
+    lv_obj_t *header;
+    lv_obj_t *theme_toggle_btn;
+    lv_obj_t *keyboard_toggle_btn;
+    lv_obj_t *layout_dropdown;
+    lv_obj_t *shutdown_btn;
+} bbx_header_widgets_t;
+
+/**
+ * Create a header bar with configurable elements.
+ *
+ * @param parent parent object (usually screen)
+ * @param config header configuration
+ * @param widgets output struct for widget references
+ * @return header object
+ */
+lv_obj_t *bbx_header_create(lv_obj_t *parent, bbx_header_config_t *config, bbx_header_widgets_t *widgets);
+
+/**
+ * Initialize header config with default values.
+ *
+ * @param config config struct to initialize
+ */
+void bbx_header_init_config(bbx_header_config_t *config);
+
+#endif /* BBX_HEADER_H */