fix(mam, log): improve datetime handling and memory management in MAM and log fetching

- Introduce static helper `_truncate_datetime_suffix()` to safely trim datetime strings, removing unwanted suffixes like timezone offsets
- Replace manual string management with auto_gchar and g_strdup for safer, clearer ownership and to prevent leaks
- Add safety checks and logging warnings for unexpected datetime string lengths or null pointers
- Refactor _mam_rsm_id_handler to use the helper function and updated string handling
- Change log_database_get_previous_chat parameters for consistent ownership semantics, avoiding double frees and mem leaks
- Overall improve stability and prevent memory leaks during log database queries

src/ui/chatwin.c

@@ -40,6 +40,7 @@
 #include <stdlib.h>
 #include <assert.h>
 
+#include "glib.h"
 #include "xmpp/chat_session.h"
 #include "window_list.h"
 #include "xmpp/roster_list.h"
@@ -585,10 +586,12 @@ _chatwin_history(ProfChatWin* chatwin, const char* const contact_barejid)
 // first entry's timestamp in the buffer is used. Flip true to prepend to buffer.
 // Timestamps should be in iso8601
 db_history_result_t
-chatwin_db_history(ProfChatWin* chatwin, const char* start_time, char* end_time, gboolean flip)
+chatwin_db_history(ProfChatWin* chatwin, const gchar* start_time, const gchar* end_time, gboolean flip)
 {
-    if (!end_time) {
-        end_time = buffer_size(((ProfWin*)chatwin)->layout->buffer) == 0 ? NULL : g_date_time_format_iso8601(buffer_get_entry(((ProfWin*)chatwin)->layout->buffer, 0)->time);
+    auto_gchar gchar* _end_time = NULL;
+    if (!end_time && buffer_size(((ProfWin*)chatwin)->layout->buffer) > 0) {
+        _end_time = g_date_time_format_iso8601(buffer_get_entry(((ProfWin*)chatwin)->layout->buffer, 0)->time);
+        end_time = _end_time;
     }
 
     GSList* history = NULL;