Named persistent workspaces: ensures unique identifiers

[arnaud-ma]

Describe your PR, what does it fix/add?

In this calll:

Hyprland/src/Compositor.cpp

Lines 3101 to 3107 in 5075850

	void CCompositor::ensurePersistentWorkspacesPresent(const std::vector<SWorkspaceRule>& rules, PHLWORKSPACE pWorkspace) {
	if (!m_lastMonitor)
	return;
	for (const auto& rule : rules) {
	if (!rule.isPersistent)
	continue;

All named persistent rules had the exact same ID, so only the first one was created. See #11146. This PR fixes this by checking ID uniqueness not only across existing workspaces, but also across persistent ones (which might not yet exist).

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

Is it ready for merging, or does it need work?

[vaxerski]

lgtm, just misses tests for this to not happen again.