Add XP tracking with level-up, kill XP formula, and server-compatible SMSG_LOG_XPGAIN support

include/game/game_handler.hpp

@@ -219,8 +219,15 @@ public:
         localPlayerLevel_ = level;
         localPlayerHealth_ = hp;
         localPlayerMaxHealth_ = maxHp;
+        playerNextLevelXp_ = xpForLevel(level);
+        playerXp_ = 0;
     }
 
+    // XP tracking (works in both single-player and server modes)
+    uint32_t getPlayerXp() const { return playerXp_; }
+    uint32_t getPlayerNextLevelXp() const { return playerNextLevelXp_; }
+    uint32_t getPlayerLevel() const { return singlePlayerMode_ ? localPlayerLevel_ : serverPlayerLevel_; }
+
     // Hearthstone callback (single-player teleport)
     using HearthstoneCallback = std::function<void()>;
     void setHearthstoneCallback(HearthstoneCallback cb) { hearthstoneCallback = std::move(cb); }
@@ -361,6 +368,9 @@ private:
     void handleGroupUninvite(network::Packet& packet);
     void handlePartyCommandResult(network::Packet& packet);
 
+    // ---- XP handler ----
+    void handleXpGain(network::Packet& packet);
+
     // ---- Phase 5 handlers ----
     void handleLootResponse(network::Packet& packet);
     void handleLootReleaseResponse(network::Packet& packet);
@@ -486,6 +496,15 @@ private:
     WorldConnectSuccessCallback onSuccess;
     WorldConnectFailureCallback onFailure;
 
+    // ---- XP tracking ----
+    uint32_t playerXp_ = 0;
+    uint32_t playerNextLevelXp_ = 0;
+    uint32_t serverPlayerLevel_ = 1;
+    void awardLocalXp(uint32_t victimLevel);
+    void levelUp();
+    static uint32_t xpForLevel(uint32_t level);
+    static uint32_t killXp(uint32_t playerLevel, uint32_t victimLevel);
+
     // ---- Single-player combat ----
     bool singlePlayerMode_ = false;
     float swingTimer_ = 0.0f;

include/game/opcodes.hpp

@@ -60,6 +60,9 @@ enum class Opcode : uint16_t {
     SMSG_GAMEOBJECT_QUERY_RESPONSE   = 0x05F,
     CMSG_SET_ACTIVE_MOVER            = 0x26A,
 
+    // ---- XP ----
+    SMSG_LOG_XPGAIN                  = 0x1D0,
+
     // ---- Phase 2: Combat Core ----
     CMSG_ATTACKSWING                 = 0x141,
     CMSG_ATTACKSTOP                  = 0x142,

include/game/world_packets.hpp

@@ -742,6 +742,25 @@ public:
     static bool parse(network::Packet& packet, SpellHealLogData& data);
 };
 
+// ============================================================
+// XP Gain
+// ============================================================
+
+/** SMSG_LOG_XPGAIN data */
+struct XpGainData {
+    uint64_t victimGuid = 0;    // 0 for non-kill XP (quest, exploration)
+    uint32_t totalXp = 0;
+    uint8_t type = 0;           // 0 = kill, 1 = non-kill
+    uint32_t groupBonus = 0;
+
+    bool isValid() const { return totalXp > 0; }
+};
+
+class XpGainParser {
+public:
+    static bool parse(network::Packet& packet, XpGainData& data);
+};
+
 // ============================================================
 // Phase 3: Spells, Action Bar, Auras
 // ============================================================

include/ui/game_screen.hpp

@@ -110,6 +110,7 @@ private:
 
     // ---- New UI renders ----
     void renderActionBar(game::GameHandler& gameHandler);
+    void renderXpBar(game::GameHandler& gameHandler);
     void renderCastBar(game::GameHandler& gameHandler);
     void renderCombatText(game::GameHandler& gameHandler);
     void renderPartyFrames(game::GameHandler& gameHandler);