docs: add AGENTS.md with project conventions

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: dzmitry-duboyski

AGENTS.md

@@ -0,0 +1,42 @@
+# AGENTS.md
+
+Python SDK for the Captcha Solver API, published on PyPI as `captcha-sdk`.
+
+## Project layout
+
+- `captcha_sdk/` — package: `client.py` (sync), `async_client.py` (async), `tasks.py`, `exceptions.py`
+- `tests/sync/`, `tests/async/` — pytest, HTTP is mocked
+- `examples/sync/`, `examples/async/` — runnable examples
+- `DEVELOPMENT.md` — setup, tests, release process
+
+## Commands
+
+```bash
+python -m pip install -e ".[dev]"   # required: async tests need pytest-asyncio
+python -m pytest -q
+python -m build && python -m twine check --strict dist/*
+```
+
+## Rules
+
+- The version is defined in two places and must match: `pyproject.toml` (`version`) and `captcha_sdk/__init__.py` (`__version__`).
+- Supported Python is 3.9+; do not use syntax or stdlib features newer than 3.9.
+
+## Commits
+
+English, [Conventional Commits](https://www.conventionalcommits.org/) format:
+
+```
+<type>: <short description in imperative mood>
+```
+
+Types: `feat`, `fix`, `docs`, `test`, `refactor`, `chore`, `ci`, `build`.
+
+Examples:
+
+```
+feat: add Tencent captcha task
+fix: handle empty solution in async client
+docs: add DEVELOPMENT.md
+chore: set version to 1.0.0
+```