magic number in chunkserver_manager.cc-2 and minor spell mistaks

`data_score > 0.95`
(line 82, 83 in flags.cc).

the disk will be concidered full. considered
Used to computer disk wordload : workload

Start by inspecting flags.cc lines 82–83 and then locate the related logic in chunkserver_manager.cc to understand the data_score threshold. Clarify or name the magic number and correct the reported “considered” and “workload” misspellings; done means the threshold’s intent is clear and the wording is corrected.

Written by the indexing model from the issue text.