core: fix data race and a unsigned int rollover (#7278)

* keybindmgr: avoid uint rollover on mouse keycode

mouse keycode is 0, and the switch case checks for 0 - 8 and rolls over,
just return early if keycode is 0.

* watchdog: avoid data races in watchdog

asan thread sanitizer reported data races in the watchdog from reading
and setting the bool variables make them std::atomic bools. also add a
atomic bool for the main thread to wait for to avoid data race when
reading the config values.

* hyprdebug: change non unicode character to name

asan created false positives and didnt like this bit, so for the sake of
easier debugging rename it to something unicode.

src/managers/KeybindManager.cpp

@@ -180,6 +180,9 @@ uint32_t CKeybindManager::stringToModMask(std::string mods) {
 }
 
 uint32_t CKeybindManager::keycodeToModifier(xkb_keycode_t keycode) {
+    if (keycode == 0)
+        return 0;
+
     switch (keycode - 8) {
         case KEY_LEFTMETA: return HL_MODIFIER_META;
         case KEY_RIGHTMETA: return HL_MODIFIER_META;