ref(theme): ensure clean reinitialization and explicitly initialize static vars

Improves code robustness by calling _theme_close() in theme_init() when the
theme was already initialized, preventing potential memory leaks or
inconsistent state.

Closes #4

src/config/theme.c

@@ -56,9 +56,9 @@
 #include "config/preferences.h"
 #include "config/color.h"
 
-static GString* theme_loc;
-static GKeyFile* theme;
-static GHashTable* defaults;
+static GString* theme_loc = NULL;
+static GKeyFile* theme = NULL;
+static GHashTable* defaults = NULL;
 
 static void _load_preferences(void);
 static void _theme_list_dir(const gchar* const dir, GSList** result);
@@ -86,6 +86,12 @@ _theme_close(void)
 void
 theme_init(const char* const theme_name)
 {
+    if(defaults || theme_loc || theme) {
+        log_warning("theme_init(): Detected non-NULL state (theme=%p, theme_loc=%p, defaults=%p). Cleaning up previous initialization.",
+            theme, theme_loc, defaults);
+        _theme_close();
+    }
+
     if (!_theme_load_file(theme_name)) {
         log_error("Loading theme %s failed.", theme_name);