Prepare 1.0.0: fix memory leaks, use-after-free bugs, and code quality issues

- Version 6.0.0 → 1.0.0, C standard gnu17 → gnu23
- Fix desktop file path (was referencing parent directory)
- global_shortcuts.c: fix systematic GVariant/GDBusProxy leaks, guint64-to-gchar*
  type mismatch, buffer overflow risk, missing malloc NULL checks, debug artifacts
- gsr-window.c: fix notification timeout use-after-free, menu object leak in
  finalize, localtime NULL check, extract active_mode_to_string helper
- gsr-stream-page.c, gsr-record-page.c, gsr-replay-page.c: fix timer source
  leak in finalize (use-after-free if destroyed while timer running)
- gsr-shortcut-accel-dialog.c: fix Pango markup injection via shortcut titles
- gsr-info.c: fix pclose UB, replace fprintf with g_warning
- gsr-config.c: include errno in fopen failure warning
- Remove unused include, stale Phase 5 comments

1 files changed, 6 insertions, 0 deletions

diff --git a/src/gsr-replay-page.c b/src/gsr-replay-page.c
index 67c7c9a..4dcbc81 100644
--- a/src/gsr-replay-page.c
+++ b/src/gsr-replay-page.c
@@ -490,6 +490,12 @@ static void
 gsr_replay_page_finalize(GObject *object)
 {
     GsrReplayPage *self = GSR_REPLAY_PAGE(object);
+
+    if (self->timer_source_id) {
+        g_source_remove(self->timer_source_id);
+        self->timer_source_id = 0;
+    }
+
     g_free(self->save_directory);
 #ifdef HAVE_X11
     g_free(self->x11_start_stop_accel);