docs(python): add module-level docstrings to public modules

[RealKai42]

Add module-level docstrings to all Python SDK modules following, with clear descriptions, key features, and runnable examples

[Copilot]

Pull request overview

This pull request adds comprehensive module-level docstrings to all Python SDK modules in the Kimi Agent SDK. The docstrings follow a consistent format with clear descriptions, key features, and runnable code examples.

Changes:

• Added module-level docstrings to six Python modules (__init__.py, _session.py, _prompt.py, _exception.py, _approval.py, _aggregator.py)
• Each docstring includes a summary, description, key classes/functions/types/exceptions listing, and practical code examples
• Examples demonstrate both high-level and low-level API usage patterns

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
python/src/kimi_agent_sdk/__init__.py	Added comprehensive package-level docstring with both high-level prompt API and low-level Session API examples
python/src/kimi_agent_sdk/_session.py	Added module docstring explaining Session class for low-level agent control with Wire message access
python/src/kimi_agent_sdk/_prompt.py	Added module docstring for high-level prompt API with examples for both yolo mode and custom approval handlers
python/src/kimi_agent_sdk/_exception.py	Added module docstring documenting SDK-specific exceptions for validation and state management
python/src/kimi_agent_sdk/_approval.py	Added module docstring explaining approval handling types and custom approval handler pattern
python/src/kimi_agent_sdk/_aggregator.py	Added module docstring for Wire message aggregation with MessageAggregator usage example

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