feat: custom zone discovery system for client auto-detection

- CustomZoneDiscovery scans directories for zone.json manifest files
- Discovers custom zones in custom_zones/ and output/ directories
- Reports: name, author, description, creature/quest availability
- Client can list all available custom expansions at startup
- Foundation for a zone selection menu in the client UI

CMakeLists.txt

@@ -590,6 +590,7 @@ set(WOWEE_SOURCES
     src/pipeline/adt_loader.cpp
     src/pipeline/wdt_loader.cpp
     src/pipeline/wowee_terrain_loader.cpp
+    src/pipeline/custom_zone_discovery.cpp
     src/pipeline/dbc_layout.cpp
 
     src/pipeline/terrain_mesh.cpp

include/pipeline/custom_zone_discovery.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+namespace wowee {
+namespace pipeline {
+
+struct CustomZoneInfo {
+    std::string name;
+    std::string author;
+    std::string description;
+    std::string directory;
+    uint32_t mapId = 9000;
+    std::vector<std::pair<int, int>> tiles;
+    bool hasCreatures = false;
+    bool hasQuests = false;
+};
+
+class CustomZoneDiscovery {
+public:
+    // Scan directories for custom zones (checks for zone.json files)
+    static std::vector<CustomZoneInfo> scan(const std::vector<std::string>& searchPaths);
+
+    // Scan a single directory
+    static std::vector<CustomZoneInfo> scanDirectory(const std::string& path);
+};
+
+} // namespace pipeline
+} // namespace wowee

src/pipeline/custom_zone_discovery.cpp

@@ -0,0 +1,63 @@
+#include "pipeline/custom_zone_discovery.hpp"
+#include "core/logger.hpp"
+#include <fstream>
+#include <filesystem>
+
+namespace wowee {
+namespace pipeline {
+
+std::vector<CustomZoneInfo> CustomZoneDiscovery::scan(const std::vector<std::string>& searchPaths) {
+    std::vector<CustomZoneInfo> results;
+    for (const auto& path : searchPaths) {
+        auto found = scanDirectory(path);
+        results.insert(results.end(), found.begin(), found.end());
+    }
+    return results;
+}
+
+std::vector<CustomZoneInfo> CustomZoneDiscovery::scanDirectory(const std::string& path) {
+    namespace fs = std::filesystem;
+    std::vector<CustomZoneInfo> results;
+
+    if (!fs::exists(path)) return results;
+
+    for (auto& entry : fs::directory_iterator(path)) {
+        if (!entry.is_directory()) continue;
+
+        std::string zoneJson = entry.path().string() + "/zone.json";
+        if (!fs::exists(zoneJson)) continue;
+
+        std::ifstream f(zoneJson);
+        if (!f) continue;
+        std::string content((std::istreambuf_iterator<char>(f)),
+                             std::istreambuf_iterator<char>());
+
+        auto findStr = [&](const std::string& key) -> std::string {
+            auto pos = content.find("\"" + key + "\"");
+            if (pos == std::string::npos) return "";
+            pos = content.find('"', content.find(':', pos) + 1);
+            if (pos == std::string::npos) return "";
+            auto end = content.find('"', pos + 1);
+            return content.substr(pos + 1, end - pos - 1);
+        };
+
+        CustomZoneInfo info;
+        info.name = findStr("mapName");
+        if (info.name.empty()) info.name = findStr("name");
+        info.author = findStr("author");
+        info.description = findStr("description");
+        info.directory = entry.path().string();
+        info.hasCreatures = fs::exists(entry.path().string() + "/creatures.json");
+        info.hasQuests = fs::exists(entry.path().string() + "/quests.json");
+
+        if (!info.name.empty()) {
+            results.push_back(info);
+            LOG_INFO("Discovered custom zone: ", info.name, " in ", info.directory);
+        }
+    }
+
+    return results;
+}
+
+} // namespace pipeline
+} // namespace wowee