feat(cdclient): make a new CDServer.sqlite off-thread and swap tables in place

CDClientSnapshot converts a copy of the client's fdb into its own
CDServer-<hash>.sqlite with the cdserver migrations applied, on its own
connection. CDClientDatabase::Reconnect opens the new file before letting go
of the old one; CDClientManager::Reload empties every table (old entries kept
alive so references from spawned objects stay valid), retires the old fdb view
and loads again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dDatabase/CDClientDatabase/CDClientManager.h

@@ -17,6 +17,20 @@ namespace CDClientManager {
 	void LoadValuesFromDatabase(const std::filesystem::path& fdbPath = {});
 	void LoadValuesFromDefaults();
 
+	/**
+	 * Loads every table again after a CDClient reload (the caller has already reconnected CDClientDatabase to the new
+	 * CDServer.sqlite). Each table's old entries are emptied out but kept alive, and so is the old fdb's view, so a
+	 * reference an entity took from a table before the reload stays valid: what is spawned keeps what it loaded, and
+	 * what is made afterwards reads the new data. Main thread only.
+	 */
+	void Reload(const std::filesystem::path& fdbPath);
+
+	// The first half of Reload: lets go of the fdb and empties every table, keeping the old entries alive
+	void ResetTables();
+
+	// How many tables ResetTables empties
+	uint32_t GetTableCount();
+
 	/**
 	 * Fetch a table from CDClient
 	 *