Stop rejecting chunks by publisher radius

[kforbro]

Boar rejected chunks whose center looked past the publisher radius. The server never re-sends them, so the player walks into a chunk Boar thinks is unloaded and gets setback forever.

• Reject only on dimension mismatch.
• Pad the eviction bound by 32 blocks — the radius bounds chunk centers, the client keeps a chunk if any part is in view.

Partially fixes #62 (unloaded-chunk half).