Filter WMO decorative geometry from collision, fix tram portal trigger IDs

Parse MOPY per-triangle flags in WMO groups and exclude detail/decorative
triangles (flag 0x04) from collision detection. This prevents invisible
walls from objects like gears and railings in WMO interiors.

Add WotLK area trigger IDs 2173/2175 to extended-range tram triggers.

include/pipeline/wmo_loader.hpp

@@ -157,6 +157,7 @@ struct WMOGroup {
     std::vector<WMOVertex> vertices;
     std::vector<uint16_t> indices;
     std::vector<WMOBatch> batches;
+    std::vector<uint8_t> triFlags;  // Per-triangle MOPY flags (0x04 = detail/no-collide)
 
     // Portals
     std::vector<WMOPortal> portals;

src/game/game_handler.cpp

@@ -8812,8 +8812,9 @@ void GameHandler::checkAreaTriggers() {
     // Deeprun Tram entrance triggers need extended range because WMO
     // collision walls block the player from reaching the trigger center.
     static const std::unordered_set<uint32_t> extendedRangeTriggers = {
-        712, 713,   // Stormwind/Ironforge → Deeprun Tram
+        712, 713,   // Stormwind/Ironforge → Deeprun Tram (classic IDs)
         2166, 2171, // Tram interior exit triggers
+        2173, 2175, // Stormwind/Ironforge tram entrance (WotLK IDs)
     };
 
     for (const auto& at : areaTriggers_) {

src/pipeline/wmo_loader.cpp

@@ -498,6 +498,16 @@ bool WMOLoader::loadGroup(const std::vector<uint8_t>& groupData,
                         group.indices.push_back(read<uint16_t>(groupData, mogpOffset));
                     }
                 }
+                else if (subChunkId == 0x4D4F5059) { // MOPY - Triangle material info
+                    // 2 bytes per triangle: flags (uint8) + materialId (uint8)
+                    // flag 0x04 = detail/decorative geometry (no collision)
+                    uint32_t triCount = subChunkSize / 2;
+                    group.triFlags.resize(triCount);
+                    for (uint32_t i = 0; i < triCount; i++) {
+                        group.triFlags[i] = read<uint8_t>(groupData, mogpOffset);
+                        read<uint8_t>(groupData, mogpOffset); // materialId (skip)
+                    }
+                }
                 else if (subChunkId == 0x4D4F4E52) { // MONR - Normals
                     uint32_t normalCount = subChunkSize / 12;
                     core::Logger::getInstance().debug("  MONR: ", normalCount, " normals for ", group.vertices.size(), " vertices");

src/rendering/wmo_renderer.cpp

@@ -1871,12 +1871,27 @@ bool WMORenderer::createGroupResources(const pipeline::WMOGroup& group, GroupRes
     resources.indexBuffer = idxBuf.buffer;
     resources.indexAlloc = idxBuf.allocation;
 
-    // Store collision geometry for floor raycasting
+    // Store collision geometry for floor raycasting.
+    // Use MOPY per-triangle flags to exclude detail/decorative geometry (flag 0x04)
+    // from collision — these are things like gears, railings, etc.
     resources.collisionVertices.reserve(group.vertices.size());
     for (const auto& v : group.vertices) {
         resources.collisionVertices.push_back(v.position);
     }
-    resources.collisionIndices = group.indices;
+    if (!group.triFlags.empty()) {
+        // Filter out non-collidable triangles
+        resources.collisionIndices.reserve(group.indices.size());
+        size_t numTris = group.indices.size() / 3;
+        for (size_t t = 0; t < numTris; t++) {
+            uint8_t flags = (t < group.triFlags.size()) ? group.triFlags[t] : 0;
+            if (flags & 0x04) continue;  // detail/decorative — skip collision
+            resources.collisionIndices.push_back(group.indices[t * 3 + 0]);
+            resources.collisionIndices.push_back(group.indices[t * 3 + 1]);
+            resources.collisionIndices.push_back(group.indices[t * 3 + 2]);
+        }
+    } else {
+        resources.collisionIndices = group.indices;
+    }
 
     // Compute actual bounding box from vertices (WMO header bboxes can be unreliable)
     if (!resources.collisionVertices.empty()) {