HF RL Explorer

Add fill value and explicit parameters to complete

Add fill value and explicit parameters to complete: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). ENH Add fill value and explicit parameters to complete Brief Description

The task

[ENH] Add `fill_value` and `explicit` parameters to `complete` # Brief Description

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.