### What problem does this PR solve?

- Consolidate HTTP API test fixtures using batch operations
(batch_add_chunks, batch_create_chat_assistants)
- Fix fixture initialization order in clear_session_with_chat_assistants
- Add new SDK API test suite for session management
(create/delete/list/update)

### Type of change

- [x] Add test cases
- [x] Refactoring

### What problem does this PR solve?

- Implement new SDK API test cases for chat assistant CRUD operations
- Enhance HTTP API concurrent tests to use as_completed for better
reliability

### Type of change

- [x] Add test cases
- [x] Refactoring

### What problem does this PR solve?

- Improve concurrent test cases by using as_completed for better
reliability
- Rename variables for clarity (chunk_num -> count)
- Add new SDK API test suite for chunk management operations
- Update HTTP API tests with consistent concurrency patterns

### Type of change

- [x] Add test cases
- [x] Refactoring

### What problem does this PR solve?

Add sdk document test cases

### Type of change

- [x] Add test cases

### What problem does this PR solve?

fix document typo in test

### Type of change

- [x] Typo

### What problem does this PR solve?

Add sdk dataset test cases

### Type of change

- [x] Add test case

### What problem does this PR solve?

- Removed hardcoded Zhipu API key from codebase
- New requirement: Tests now require ZHIPU_AI_API_KEY environment
variable
  Example: export ZHIPU_AI_API_KEY=your_api_key_here

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

### What problem does this PR solve?

Move test cases only - CI still runs tests under sdk/python

### Type of change

- [x] Refactoring