chore(refactor): god-object decomposition and mega-file splits

Split all mega-files by single-responsibility concern and
partially extracting AudioCoordinator and
OverlaySystem from the Renderer facade. No behavioral changes.

Splits:
- game_handler.cpp (5,247 LOC) → core + callbacks + packets (3 files)
- world_packets.cpp (4,453 LOC) → economy/entity/social/world (4 files)
- game_screen.cpp  (5,786 LOC) → core + frames + hud + minimap (4 files)
- m2_renderer.cpp  (3,343 LOC) → core + instance + particles + render (4 files)
- chat_panel.cpp   (3,140 LOC) → core + commands + utils (3 files)
- entity_spawner.cpp (2,750 LOC) → core + player + processing (3 files)

Extractions:
- AudioCoordinator: include/audio/ + src/audio/ (owned by Renderer)
- OverlaySystem: include/rendering/ + src/rendering/overlay_system.*

CMakeLists.txt: registered all 17 new translation units.
Related handler/callback files: minor include fixups post-split.

src/core/animation_callback_handler.cpp

@@ -51,7 +51,7 @@ bool AnimationCallbackHandler::updateCharge(float deltaTime) {
         dir *= glm::inversesqrt(dirLenSq);
         float yawDeg = glm::degrees(std::atan2(dir.x, dir.y));
         renderer_.setCharacterYaw(yawDeg);
-        renderer_.emitChargeEffect(renderPos, dir);
+        if (auto* ac = renderer_.getAnimationController()) ac->emitChargeEffect(renderPos, dir);
     }
 
     // Sync to game handler
@@ -69,8 +69,8 @@ bool AnimationCallbackHandler::updateCharge(float deltaTime) {
     // Charge complete
     if (t >= 1.0f) {
         chargeActive_ = false;
-        renderer_.setCharging(false);
-        renderer_.stopChargeEffect();
+        if (auto* ac = renderer_.getAnimationController()) ac->setCharging(false);
+        if (auto* ac = renderer_.getAnimationController()) ac->stopChargeEffect();
         renderer_.getCameraController()->setExternalFollow(false);
         renderer_.getCameraController()->setExternalMoving(false);
 
@@ -95,7 +95,7 @@ bool AnimationCallbackHandler::updateCharge(float deltaTime) {
                 }
             }
             gameHandler_.startAutoAttack(chargeTargetGuid_);
-            renderer_.triggerMeleeSwing();
+            if (auto* ac = renderer_.getAnimationController()) ac->triggerMeleeSwing();
         }
 
         // Send movement heartbeat so server knows our new position
@@ -157,11 +157,11 @@ void AnimationCallbackHandler::setupCallbacks() {
         // Disable player input, play charge animation
         renderer_.getCameraController()->setExternalFollow(true);
         renderer_.getCameraController()->clearMovementInputs();
-        renderer_.setCharging(true);
+        if (auto* ac = renderer_.getAnimationController()) ac->setCharging(true);
 
         // Start charge visual effect (red haze + dust)
         glm::vec3 chargeDir = glm::normalize(endRender - startRender);
-        renderer_.startChargeEffect(startRender, chargeDir);
+        if (auto* ac = renderer_.getAnimationController()) ac->startChargeEffect(startRender, chargeDir);
 
         // Play charge whoosh sound (try multiple paths)
         auto& audio = audio::AudioEngine::instance();

src/core/application.cpp

@@ -934,7 +934,7 @@ void Application::setState(AppState newState) {
                 uint32_t oldInst = renderer->getCharacterInstanceId();
                 if (oldInst > 0) {
                     renderer->setCharacterFollow(0);
-                    renderer->clearMount();
+                    if (auto* ac = renderer->getAnimationController()) ac->clearMount();
                     renderer->getCharacterRenderer()->removeInstance(oldInst);
                 }
             }
@@ -975,11 +975,11 @@ void Application::setState(AppState newState) {
                     if (renderer) {
                         // Ranged auto-attack spells: Auto Shot (75), Shoot (5019), Throw (2764)
                         if (spellId == 75 || spellId == 5019 || spellId == 2764) {
-                            renderer->triggerRangedShot();
+                            if (auto* ac = renderer->getAnimationController()) ac->triggerRangedShot();
                         } else if (spellId != 0) {
-                            renderer->triggerSpecialAttack(spellId);
+                            if (auto* ac = renderer->getAnimationController()) ac->triggerSpecialAttack(spellId);
                         } else {
-                            renderer->triggerMeleeSwing();
+                            if (auto* ac = renderer->getAnimationController()) ac->triggerMeleeSwing();
                         }
                     }
                 });
@@ -1118,7 +1118,7 @@ void Application::logoutToLogin() {
         if (auto* questMarkers = renderer->getQuestMarkerRenderer()) {
             questMarkers->clear();
         }
-        renderer->clearMount();
+        if (auto* ac = renderer->getAnimationController()) ac->clearMount();
         renderer->setCharacterFollow(0);
         if (auto* music = audioCoordinator_ ? audioCoordinator_->getMusicManager() : nullptr) {
             music->stopMusic(0.0f);
@@ -1346,13 +1346,13 @@ void Application::update(float deltaTime) {
                                 // Tilt the mount/character model to match flight direction
                                 // (taxi flight uses setTaxiOrientationCallback for this instead)
                                 if (gameHandler->isPlayerFlying() && gameHandler->isMounted()) {
-                                    renderer->setMountPitchRoll(pitchRad, 0.0f);
+                                    if (auto* ac = renderer->getAnimationController()) ac->setMountPitchRoll(pitchRad, 0.0f);
                                 }
                             }
                         }
                     } else if (gameHandler->isMounted()) {
                         // Reset mount pitch when not flying
-                        renderer->setMountPitchRoll(0.0f, 0.0f);
+                        if (auto* ac = renderer->getAnimationController()) ac->setMountPitchRoll(0.0f, 0.0f);
                     }
                 }
 
@@ -1454,14 +1454,14 @@ void Application::update(float deltaTime) {
                 }
                 bool idleOrbit = renderer->getCameraController()->isIdleOrbit();
                 if (idleOrbit && !idleYawned_ && renderer) {
-                    renderer->playEmote("yawn");
+                    if (auto* ac = renderer->getAnimationController()) ac->playEmote("yawn");
                     idleYawned_ = true;
                 } else if (!idleOrbit) {
                     idleYawned_ = false;
                 }
                 }
                 if (renderer) {
-                    renderer->setTaxiFlight(onTaxi);
+                    if (auto* ac = renderer->getAnimationController()) ac->setTaxiFlight(onTaxi);
                 }
                 if (renderer && renderer->getTerrainManager()) {
                 renderer->getTerrainManager()->setStreamingEnabled(true);

src/core/audio_callback_handler.cpp

@@ -2,6 +2,8 @@
 #include "core/coordinates.hpp"
 #include "core/logger.hpp"
 #include "rendering/renderer.hpp"
+#include "rendering/animation_controller.hpp"
+#include "pipeline/asset_manager.hpp"
 #include "pipeline/dbc_loader.hpp"
 #include "game/game_handler.hpp"
 #include "audio/audio_coordinator.hpp"
@@ -50,7 +52,7 @@ void AudioCallbackHandler::setupCallbacks() {
             uiManager_->getGameScreen().toastManager().triggerDing(newLevel);
         }
         if (renderer_) {
-            renderer_->triggerLevelUpEffect(renderer_->getCharacterPosition());
+            if (auto* ac = renderer_->getAnimationController()) ac->triggerLevelUpEffect(renderer_->getCharacterPosition());
         }
     });
 
@@ -108,7 +110,7 @@ void AudioCallbackHandler::setupCallbacks() {
         if (entity) {
             glm::vec3 canonical(entity->getX(), entity->getY(), entity->getZ());
             glm::vec3 renderPos = core::coords::canonicalToRender(canonical);
-            renderer_->triggerLevelUpEffect(renderPos);
+            if (auto* ac = renderer_->getAnimationController()) ac->triggerLevelUpEffect(renderPos);
         }
 
         // Show chat message if in group

src/core/transport_callback_handler.cpp

@@ -4,6 +4,7 @@
 #include "core/coordinates.hpp"
 #include "core/logger.hpp"
 #include "rendering/renderer.hpp"
+#include "rendering/animation_controller.hpp"
 #include "rendering/character_renderer.hpp"
 #include "rendering/camera_controller.hpp"
 #include "rendering/terrain_manager.hpp"
@@ -37,7 +38,7 @@ void TransportCallbackHandler::setupCallbacks() {
                 entitySpawner_.clearMountState();
             }
             entitySpawner_.setMountDisplayId(0);
-            renderer_.clearMount();
+            if (auto* ac = renderer_.getAnimationController()) ac->clearMount();
             LOG_INFO("Dismounted");
             return;
         }
@@ -106,7 +107,7 @@ void TransportCallbackHandler::setupCallbacks() {
             renderer_.getCameraController()->setFacingYaw(yawDegrees);
             renderer_.setCharacterYaw(yawDegrees);
             // Set mount pitch and roll for realistic flight animation
-            renderer_.setMountPitchRoll(pitch, roll);
+            if (auto* ac = renderer_.getAnimationController()) ac->setMountPitchRoll(pitch, roll);
         }
     });
 

src/core/world_entry_callback_handler.cpp

@@ -4,6 +4,7 @@
 #include "core/world_loader.hpp"
 #include "core/logger.hpp"
 #include "rendering/renderer.hpp"
+#include "rendering/animation_controller.hpp"
 #include "rendering/camera_controller.hpp"
 #include "rendering/terrain_manager.hpp"
 #include "rendering/wmo_renderer.hpp"

src/core/world_loader.cpp

@@ -11,6 +11,7 @@
 #include "core/coordinates.hpp"
 #include "core/logger.hpp"
 #include "rendering/renderer.hpp"
+#include "rendering/animation_controller.hpp"
 #include "rendering/vk_context.hpp"
 #include "rendering/camera.hpp"
 #include "rendering/camera_controller.hpp"
@@ -290,7 +291,7 @@ void WorldLoader::loadOnlineWorldTerrain(uint32_t mapId, float x, float y, float
             if (auto* questMarkers = renderer_->getQuestMarkerRenderer()) {
                 questMarkers->clear();
             }
-            renderer_->clearMount();
+            if (auto* ac = renderer_->getAnimationController()) ac->clearMount();
         }
 
         // Clear application-level instance tracking (after renderer cleanup)
@@ -416,7 +417,7 @@ void WorldLoader::loadOnlineWorldTerrain(uint32_t mapId, float x, float y, float
                     uint32_t oldInst = renderer_->getCharacterInstanceId();
                     if (oldInst > 0) {
                         renderer_->setCharacterFollow(0);
-                        renderer_->clearMount();
+                        if (auto* ac = renderer_->getAnimationController()) ac->clearMount();
                         renderer_->getCharacterRenderer()->removeInstance(oldInst);
                     }
                 }