use-of-uninitialized-value in cellToVertex

use-of-uninitialized-value in cellToVertex: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). MemorySanitizer: use-of-uninitialized-value in function cellToVertex in file h3/src/h3lib/lib/vertex.c