Performance optimizations and collision improvements

Performance:
- Remove expensive inverse() from all vertex shaders (terrain, WMO, M2, water, character)
- Add uniform location caching to avoid repeated glGetUniformLocation calls
- Add proper frustum culling for WMO groups using AABB intersection
- Add distance-based culling for WMO and M2 instances
- Add cleanup of unused M2/WMO models when tiles unload

Collision & Movement:
- Add M2 doodad collision detection (fences, boxes, etc.)
- Reduce character eye height (5.0 -> 1.8) and collision radius (2.5 -> 0.5)
- Enable WoW-style movement speed by default (14 units/sec run, 5 walk, 9 back)
- Fix emote grammar ("You waves." -> "You wave.")

Misc:
- Rename window title to "Wowee"

include/rendering/m2_renderer.hpp

@@ -116,6 +116,23 @@ public:
      */
     void clear();
 
+    /**
+     * Remove models that have no instances referencing them
+     * Call periodically to free GPU memory
+     */
+    void cleanupUnusedModels();
+
+    /**
+     * Check collision with M2 objects and adjust position
+     * @param from Starting position
+     * @param to Desired position
+     * @param adjustedPos Output adjusted position
+     * @param playerRadius Collision radius of player
+     * @return true if collision occurred
+     */
+    bool checkCollision(const glm::vec3& from, const glm::vec3& to,
+                        glm::vec3& adjustedPos, float playerRadius = 0.5f) const;
+
     // Stats
     uint32_t getModelCount() const { return static_cast<uint32_t>(models.size()); }
     uint32_t getInstanceCount() const { return static_cast<uint32_t>(instances.size()); }