feat(editor): Wowee Content Pack (.wcp) format for zone distribution

- WCP format: simple binary archive with magic header, JSON manifest,
  and concatenated file data. Not tied to any proprietary format.
- ContentPacker::packZone(): bundles all zone files from output dir
  into a single .wcp file (terrain, objects, creatures, quests, manifest)
- ContentPacker::unpackZone(): extracts .wcp to a directory
- ContentPacker::readInfo(): reads pack metadata without extracting
- Format: "WCP1" magic + fileCount + infoJSON + file table + data
- Foundation for distributing custom zones to other wowee users
  and private servers

Note: currently bundles ADT/WDT files as-is. Future: convert terrain
to open format (heightmap + JSON) for fully open redistribution.

tools/editor/content_pack.hpp

@@ -0,0 +1,40 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+namespace wowee {
+namespace editor {
+
+struct ContentPackInfo {
+    std::string name;
+    std::string author;
+    std::string description;
+    std::string version = "1.0";
+    uint32_t mapId = 9000;
+    std::string format = "wcp-1.0";
+
+    struct FileEntry {
+        std::string path;        // path inside pack
+        std::string category;    // terrain, object, creature, quest, texture, model
+        uint64_t size = 0;
+    };
+    std::vector<FileEntry> files;
+};
+
+class ContentPacker {
+public:
+    // Pack all zone data from output directory into a .wcp file
+    static bool packZone(const std::string& outputDir, const std::string& mapName,
+                          const std::string& destPath, const ContentPackInfo& info);
+
+    // Unpack a .wcp file to a directory
+    static bool unpackZone(const std::string& wcpPath, const std::string& destDir);
+
+    // Read pack info without extracting
+    static bool readInfo(const std::string& wcpPath, ContentPackInfo& info);
+};
+
+} // namespace editor
+} // namespace wowee