feat: add helpers to expose package version and server version API

[ravivarmanr26]

Closes #646

There was no clean way to check the installed package version or query the running Ollama server version from Python without resorting to workarounds like parsing package metadata manually or catching exceptions.

This PR exposes two things:

• ollama.__version__ : already existed internally in _client.py for the User-Agent header, just not exported. Now re-exported via __init__.py.
• ollama.version() : top-level alias for Client.version(), which calls GET /api/version and returns the version string. AsyncClient.version() added for completeness.

Usage

import ollama

print(ollama.__version__)   # package version e.g. "0.6.1"
print(ollama.version())     # server version e.g. "0.18.2"

Changes

• ollama/__init__.py : exports __version__ and wires version as a top-level alias
• ollama/_client.py : adds version() to Client and AsyncClient
• tests/test_client.py : 4 new tests: package attribute check, sync/async , missing field edge case

Tests

All tests pass locally.
Command used:
pytest tests/test_client.py

Result :

76 passed in 2.32s