[FEATURE] (fileset) support tencent cosn storage

### Describe the feature

Optimization methods of cosn:
1. Performance optimization:
a. Combined with the architecture of COS fusion bucket, separate metadata flow and data flow to achieve high-performance file semantic access
b. Based on COS distributed metadata engine, provide high-performance metadata access
c. Provide high-concurrency data flow through pre-reading strategy, block processing and other means
2. Integrate Tencent Cloud service role authentication capabilities to improve access security
3. Integrate Tencent Cloud log reporting capabilities, support task-level log reporting, and improve observability

### Motivation

_No response_

### Describe the solution

_No response_

### Additional context

_No response_

Start by locating the fileset storage integration and existing cloud-storage implementations in the repository. Compare the current support with the issue's COSN requirements—performance optimization, Tencent Cloud service-role authentication, and task-level log reporting—and define completion criteria before implementation.

Written by the indexing model from the issue text.