perf: eliminate ~70 unnecessary sqrt ops per frame, optimize caches and threading

Squared distance optimizations across 30 files:
- Convert glm::length() comparisons to glm::dot() (no sqrt)
- Use glm::inversesqrt() for check-then-normalize patterns (1 rsqrt vs 2 sqrt)
- Defer sqrt to after early-out checks in collision/movement code
- Hottest paths: camera_controller (21), weather particles, WMO collision,
  transport movement, creature interpolation, nameplate culling

Container and algorithm improvements:
- std::map<string> → std::unordered_map for asset/DBC/MPQ/warden caches
- std::mutex → std::shared_mutex for asset_manager and mpq_manager caches
- std::sort → std::partial_sort in lighting_manager (top-2 of N volumes)
- Double-lookup find()+operator[] → insert_or_assign in game_handler
- Add reserve() for per-frame vectors: weather, swim_effects, WMO/M2 collision

Threading and synchronization:
- Replace 1ms busy-wait polling with condition_variable in character_renderer
- Move timestamp capture before mutex in logger
- Use memory_order_acquire/release for normal map completion signaling

API additions:
- DBC getStringView()/getStringViewByOffset() for zero-copy string access
- Parse creature display IDs from SMSG_CREATURE_QUERY_SINGLE_RESPONSE

src/rendering/minimap.cpp

@@ -421,10 +421,11 @@ void Minimap::compositePass(VkCommandBuffer cmd, const glm::vec3& centerWorldPos
     const auto now = std::chrono::steady_clock::now();
     bool needsRefresh = !hasCachedFrame;
     if (!needsRefresh) {
-        float moved = glm::length(glm::vec2(centerWorldPos.x - lastUpdatePos.x,
-                                             centerWorldPos.y - lastUpdatePos.y));
+        float mdx = centerWorldPos.x - lastUpdatePos.x;
+        float mdy = centerWorldPos.y - lastUpdatePos.y;
+        float movedSq = mdx * mdx + mdy * mdy;
         float elapsed = std::chrono::duration<float>(now - lastUpdateTime).count();
-        needsRefresh = (moved >= updateDistance) || (elapsed >= updateIntervalSec);
+        needsRefresh = (movedSq >= updateDistance * updateDistance) || (elapsed >= updateIntervalSec);
     }
 
     // Also refresh if player crossed a tile boundary