Add 3D level-up effect using LevelUp.m2 spell model

Replace 2D screen-space ding rings with real WoW LevelUp.m2 particle/geometry
effect. Fix FBlock particle color parsing (C3Vector floats, not CImVector bytes)
which was producing blue/red instead of golden yellow. Spell effect models bypass
particle dampeners, glow sprite conversion, Mod→Additive blend override, and all
collision (floor/wall/camera) to prevent camera zoom-in. Other players' level-ups
trigger the 3D effect at their position with group chat notification. F7 hotkey
for testing.

src/rendering/levelup_effect.cpp

@@ -0,0 +1,71 @@
+#include "rendering/levelup_effect.hpp"
+#include "rendering/m2_renderer.hpp"
+#include "pipeline/m2_loader.hpp"
+#include "core/logger.hpp"
+
+namespace wowee {
+namespace rendering {
+
+LevelUpEffect::LevelUpEffect() = default;
+LevelUpEffect::~LevelUpEffect() = default;
+
+bool LevelUpEffect::loadModel(M2Renderer* m2Renderer,
+                               const std::vector<uint8_t>& m2FileData,
+                               const std::vector<uint8_t>& skinFileData) {
+    if (!m2Renderer || m2FileData.empty()) return false;
+
+    m2Renderer_ = m2Renderer;
+
+    pipeline::M2Model model = pipeline::M2Loader::load(m2FileData);
+    // Spell effect M2s may have no geometry (particle-only), so don't require isValid()
+    if (model.vertices.empty() && model.particleEmitters.empty()) {
+        LOG_WARNING("LevelUpEffect: M2 has no vertices and no particle emitters");
+        return false;
+    }
+
+    if (!skinFileData.empty() && model.version >= 264) {
+        pipeline::M2Loader::loadSkin(skinFileData, model);
+    }
+
+    if (!m2Renderer_->loadModel(model, MODEL_ID)) {
+        LOG_WARNING("LevelUpEffect: failed to load model to GPU");
+        return false;
+    }
+
+    modelLoaded_ = true;
+    LOG_INFO("LevelUpEffect: loaded LevelUp.m2 — vertices=", model.vertices.size(),
+             " indices=", model.indices.size(),
+             " emitters=", model.particleEmitters.size(),
+             " batches=", model.batches.size());
+    return true;
+}
+
+void LevelUpEffect::trigger(const glm::vec3& position) {
+    if (!modelLoaded_ || !m2Renderer_) return;
+
+    uint32_t instanceId = m2Renderer_->createInstance(MODEL_ID, position,
+                                                       glm::vec3(0.0f), 1.0f);
+    if (instanceId == 0) {
+        LOG_WARNING("LevelUpEffect: failed to create instance");
+        return;
+    }
+
+    activeEffects_.push_back({instanceId, 0.0f});
+}
+
+void LevelUpEffect::update(float deltaTime) {
+    if (activeEffects_.empty() || !m2Renderer_) return;
+
+    for (auto it = activeEffects_.begin(); it != activeEffects_.end(); ) {
+        it->elapsed += deltaTime;
+        if (it->elapsed >= EFFECT_DURATION) {
+            m2Renderer_->removeInstance(it->instanceId);
+            it = activeEffects_.erase(it);
+        } else {
+            ++it;
+        }
+    }
+}
+
+} // namespace rendering
+} // namespace wowee