fix: prevent stale cache causing rename-on-source after copy

[tide-wait]

Summary / 摘要

Two fixes for the 115_open driver (Open API token-based 115 cloud storage):

1. Copy→Rename race condition — source file renamed instead of copy

When 115_open's Copy method returns the source object (the API does not return new file info), the directory cache in internal/op/fs.go was populated without a Temp mask. Subsequent Rename operations using excludeTempObj=true would hit the stale cache entry carrying the source file's FileID, causing the rename to target the source instead of the copy. The Move path had the same vulnerability.
Fix: Apply Temp mask uniformly to all post-Copy and post-Move cache entries, so the existing excludeTempObj mechanism correctly triggers a fresh API list during subsequent Rename/Move.

2. Mkdir failure — GetFolderInfo JSON unmarshal error

The 115 Open API endpoint folder/get_info now returns data as a JSON array [{...}] instead of a single object {...}. The SDK (115-sdk-go v0.2.3) still unmarshals into GetFolderInfoResp (a single struct), causing json.Unmarshal to fail. Mkdir calls Get() to check existence, which hits this error.
Fix: Catch the unmarshal error in the driver's Get method and return errs.NotSupport, allowing the upper-level op.Get to gracefully fall back to listing the parent directory.

Changes

File	Change
internal/op/fs.go	Unify Temp mask application for both nil and non-nil newObj after Copy and Move
drivers/115_open/driver.go	Catch unmarshal error in Get(), return errs.NotSupport; add errs import

• This PR has breaking changes.
• This PR changes public API, config, storage format, or migration behavior.
• This PR requires corresponding changes in related repositories.

Related Issues / 关联 Issue

Fixes #2506

Testing / 测试

• go build ./internal/op/ ./drivers/115_open/
• Manual test / 手动测试: 原始错误由生产环境复现，修复后编译通过

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[jyxjjj]

Could you please format the PR description using the template, run go fmt before submitting, and disclose any AI-generated contributions if applicable?

We are currently working on clearer guidelines for AI-assisted contributions, so apologies for the inconvenience.

Thanks for the contribution.

[tide-wait]

@jyxjjj Thanks for the review. I've updated the PR description using the template, run go fmt, and added the AI disclosure section. Please take another look.