Improve public API surface and top-level exports

[ajshedivy]

Summary

Key classes that users need regularly are not exported from the top-level package, forcing users to know internal module paths. Additionally, the library lacks common Python conventions like environment variable configuration and a __version__ attribute.

Current Problems

1. Missing top-level exports

mapepire_python/__init__.py currently exports:

__all__ = [
    "apilevel", "threadsafety", "paramstyle",
    "DatabaseError", "DataError", "Error", "InterfaceError",
    "InternalError", "NotSupportedError", "OperationalError",
    "ProgrammingError", "IntegrityError", "Warning",
    "CONNECTION_CLOSED", "convert_runtime_errors",
    "connect", "Connection", "Cursor",
]

Missing exports that users need:

• DaemonServer — the primary credentials class (users must do from mapepire_python.data_types import DaemonServer)
• SQLJob — the core sync client (from mapepire_python.client.sql_job import SQLJob)
• PoolJob — the core async client (from mapepire_python.pool.pool_job import PoolJob)
• Pool, PoolOptions — connection pooling (from mapepire_python.pool.pool_client import Pool)
• QueryOptions — query configuration
• QueryState, JobStatus — useful enums for checking state
• QueryResult — the result type users work with

2. No __version__ attribute

Version is defined in version.py but not re-exported:

# Users expect this to work:
import mapepire_python
print(mapepire_python.__version__)  # AttributeError

3. No environment variable configuration

Most Python database clients support environment variables for connection configuration (psycopg2, asyncpg, etc.). mapepire-python requires explicit credentials in every call.

Proposed environment variables:

• MAPEPIRE_HOST — server hostname
• MAPEPIRE_PORT — server port (default: 8076)
• MAPEPIRE_USER — database user
• MAPEPIRE_PASSWORD — database password
• MAPEPIRE_CA_PATH — path to CA certificate file

This enables:

# With env vars set, just:
with connect() as conn:
    result = conn.execute("SELECT ...").fetchone()

4. No async connect() at the top level

The async connection requires a separate import:

from mapepire_python.asyncio.connection import connect  # Not discoverable

Should be accessible as:

from mapepire_python import async_connect
# or
from mapepire_python.asyncio import connect

Proposed Changes

1. Add missing classes to __init__.py __all__:

   • DaemonServer, SQLJob, PoolJob, Pool, PoolOptions
   • QueryOptions, QueryResult, QueryState, JobStatus

2. Add __version__ re-exported from version.py

3. Add environment variable support to DaemonServer or connect():

   • Fall back to env vars when parameters are not provided
   • Document the supported env var names

4. Add async_connect to top-level exports or document the async import path clearly

Files to Modify

• mapepire_python/__init__.py — Add exports, __version__, async_connect
• mapepire_python/data_types.py — Add env var fallback to DaemonServer
• mapepire_python/base_job.py — Support env var config in _parse_connection_input()

Acceptance Criteria

• All commonly-used classes importable from mapepire_python directly
• mapepire_python.__version__ returns the current version string
• connect() works with no arguments when env vars are set
• Async connect is accessible from a documented top-level path
• Existing tests still pass
• README updated with new import patterns and env var documentation