Vanilla/Turtle WoW support: M2 loading, bone parsing, textures, auth

- Vanilla M2 bone struct (108 bytes) with 28-byte animation tracks
- Version-aware bone parsing (vanilla vs WotLK format detection)
- Fix CharSections.dbc field layout for vanilla (variation/color at 4-5)
- Remove broken CharSections.csv files (all fields marked as strings)
- Expansion data reload on profile switch (DBC cache clear, layout reload)
- Vanilla packet encryption (VanillaCrypt XOR-based header crypt)
- Extended character preview geoset range (0-99) for vanilla models
- DBC cache clear support in AssetManager

src/auth/vanilla_crypt.cpp

@@ -0,0 +1,34 @@
+#include "auth/vanilla_crypt.hpp"
+
+namespace wowee {
+namespace auth {
+
+void VanillaCrypt::init(const std::vector<uint8_t>& sessionKey) {
+    key_ = sessionKey;
+    sendIndex_ = 0;
+    sendPrev_ = 0;
+    recvIndex_ = 0;
+    recvPrev_ = 0;
+}
+
+void VanillaCrypt::encrypt(uint8_t* data, size_t length) {
+    for (size_t i = 0; i < length; ++i) {
+        uint8_t x = (data[i] ^ key_[sendIndex_]) + sendPrev_;
+        sendIndex_ = (sendIndex_ + 1) % key_.size();
+        data[i] = x;
+        sendPrev_ = x;
+    }
+}
+
+void VanillaCrypt::decrypt(uint8_t* data, size_t length) {
+    for (size_t i = 0; i < length; ++i) {
+        uint8_t enc = data[i];
+        uint8_t x = (enc - recvPrev_) ^ key_[recvIndex_];
+        recvIndex_ = (recvIndex_ + 1) % key_.size();
+        recvPrev_ = enc;
+        data[i] = x;
+    }
+}
+
+} // namespace auth
+} // namespace wowee