[TheCrazy17]

Summary

Fixes water elements created in a dimension different from the local player's current dimension being deleted instead of just hidden.

Motivation

Resolves #849. CClientWater's constructor calls RelateDimension() right away, comparing its own dimension (still the default 0, since the real value hasn't been read from the network packet yet) against the local player's current dimension. On a mismatch it calls Destroy() instead of Create(), leaving m_pPoly null.

Packet_EntityAdd treated that as a creation failure: if (!pWater->Exists()) { delete pWater; pWater = NULL; }, deleting the element right after construction, before the packet handler even reaches the line further down that applies the water's real dimension (pEntity->SetDimension(usDimension)). That check dates back to when water had no dimension concept and m_pPoly == nullptr could only mean the native call genuinely failed (invalid vertices, water pool full); it was never updated when dimension support was added, so it can no longer tell a real failure apart from water that's just correctly waiting for its dimension to be applied.

Test plan

Created water server-side in dimension 0 while standing in dimension 1, then switched to dimension 0. Before the fix, the water never appeared; after the fix, it shows up correctly once dimensions match.

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.