Restructure inventory UI, add vendor selling, camera intro on all spawns, and quest log

Split inventory into bags-only (B key) and character screen (C key). Vendor window
auto-opens bags with sell prices on hover and right-click to sell. Add camera intro
pan on all login/spawn/teleport/hearthstone events and idle orbit after 2 minutes.
Add quest log UI, SMSG_MONSTER_MOVE handling, deferred creature spawn queue, and
creature fade-in/movement interpolation for online mode.

include/rendering/camera_controller.hpp

@@ -192,6 +192,11 @@ private:
     float introEndPitch = -5.0f;
     float introStartDistance = 12.0f;
     float introEndDistance = 10.0f;
+
+    // Idle camera: triggers intro pan after IDLE_TIMEOUT seconds of no input
+    float idleTimer_ = 0.0f;
+    bool idleOrbit_ = false;  // true when current intro pan is an idle orbit (loops)
+    static constexpr float IDLE_TIMEOUT = 120.0f; // 2 minutes
 };
 
 } // namespace rendering

include/rendering/character_renderer.hpp

@@ -61,6 +61,9 @@ public:
 
     void setInstancePosition(uint32_t instanceId, const glm::vec3& position);
     void setInstanceRotation(uint32_t instanceId, const glm::vec3& rotation);
+    void moveInstanceTo(uint32_t instanceId, const glm::vec3& destination, float durationSeconds);
+    void startFadeIn(uint32_t instanceId, float durationSeconds);
+    const pipeline::M2Model* getModelData(uint32_t modelId) const;
     void setActiveGeosets(uint32_t instanceId, const std::unordered_set<uint16_t>& geosets);
     void setGroupTextureOverride(uint32_t instanceId, uint16_t geosetGroup, GLuint textureId);
     void setInstanceVisible(uint32_t instanceId, bool visible);
@@ -130,6 +133,18 @@ private:
         // Weapon attachments (weapons parented to this instance's bones)
         std::vector<WeaponAttachment> weaponAttachments;
 
+        // Opacity (for fade-in)
+        float opacity = 1.0f;
+        float fadeInTime = 0.0f;     // elapsed fade time (seconds)
+        float fadeInDuration = 0.0f; // total fade duration (0 = no fade)
+
+        // Movement interpolation
+        bool isMoving = false;
+        glm::vec3 moveStart{0.0f};
+        glm::vec3 moveEnd{0.0f};
+        float moveDuration = 0.0f;   // seconds
+        float moveElapsed = 0.0f;
+
         // Override model matrix (used for weapon instances positioned by parent bone)
         bool hasOverrideModelMatrix = false;
         glm::mat4 overrideModelMatrix{1.0f};

include/rendering/renderer.hpp

@@ -123,6 +123,10 @@ public:
     bool isMoving() const;
     void triggerMeleeSwing();
 
+    // Selection circle for targeted entity
+    void setSelectionCircle(const glm::vec3& pos, float radius, const glm::vec3& color);
+    void clearSelectionCircle();
+
     // CPU timing stats (milliseconds, last frame).
     double getLastUpdateMs() const { return lastUpdateMs; }
     double getLastRenderMs() const { return lastRenderMs; }
@@ -224,6 +228,18 @@ private:
     // Target facing
     const glm::vec3* targetPosition = nullptr;
 
+    // Selection circle rendering
+    uint32_t selCircleVAO = 0;
+    uint32_t selCircleVBO = 0;
+    uint32_t selCircleShader = 0;
+    int selCircleVertCount = 0;
+    void initSelectionCircle();
+    void renderSelectionCircle(const glm::mat4& view, const glm::mat4& projection);
+    glm::vec3 selCirclePos{0.0f};
+    glm::vec3 selCircleColor{1.0f, 0.0f, 0.0f};
+    float selCircleRadius = 1.5f;
+    bool selCircleVisible = false;
+
     // Footstep event tracking (animation-driven)
     uint32_t footstepLastAnimationId = 0;
     float footstepLastNormTime = 0.0f;