fix(freeze): allow right-clicking air-backed frozen blocks

[twme-ai]

Summary

• scan the player sight line when a freeze-mode interaction is reported as RIGHT_CLICK_AIR
• resolve registered frozen locations even when their backing world block is air
• stop at the nearest normally targetable block to prevent selecting frozen blocks through walls

Context

The latest 0.5.2 release keeps frozen blocks as air and renders them with display/fake-barrier state. Bukkit block ray tracing therefore returns no target for a direct right-click on the frozen location. Main now uses physical barriers, but this fallback keeps the interaction correct for air-backed frozen state and maintenance backports.

Verification

• mvn test
• mvn package
• git diff --check upstream/main...HEAD