feat(db): bbb_autosave table for the client's BBB autosave

The client sends SetBBBAutosave (996) with the model being built every five
minutes, before an AFK kick and before quitting, and expects the server to
rebuild an unfinished model later (RebuildBBBAutosaveMsg). This keeps the
last one per character with the model items that were in the BBB inventory
at the time. MySQL 82 / SQLite 65; parity test included.

Refs #1632

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

dDatabase/GameDatabase/ITables/BbbAutosaveItems.h

@@ -0,0 +1,38 @@
+#ifndef __BBBAUTOSAVEITEMS__H__
+#define __BBBAUTOSAVEITEMS__H__
+
+#include <cstdlib>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "dCommonVars.h"
+
+// bbb_autosave.source_items: the item ids as a comma separated list
+namespace BbbAutosaveItems {
+	inline std::string Join(const std::vector<LWOOBJID>& items) {
+		std::string out;
+		for (const auto id : items) {
+			if (!out.empty()) out += ',';
+			out += std::to_string(id);
+		}
+		return out;
+	}
+
+	inline std::vector<LWOOBJID> Parse(const std::string_view text) {
+		std::vector<LWOOBJID> items;
+		size_t start = 0;
+		while (start < text.size()) {
+			auto end = text.find(',', start);
+			if (end == std::string_view::npos) end = text.size();
+			const std::string part(text.substr(start, end - start));
+			char* parsedEnd = nullptr;
+			const auto id = std::strtoll(part.c_str(), &parsedEnd, 10);
+			if (parsedEnd != part.c_str() && id != 0) items.push_back(id);
+			start = end + 1;
+		}
+		return items;
+	}
+}
+
+#endif //!__BBBAUTOSAVEITEMS__H__