fix: add logging for start_session details

[psschwei]

Fixes #39

Adds an info-level log message when start_session() is called, displaying the backend name, model ID (resolved for the specific backend), context type, and model options (if provided).

[mergify]

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🟢 Enforce conventional commit

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Make sure that we follow https://www.conventionalcommits.org/en/v1.0.0/

• title ~= ^(fix|feat|docs|style|refactor|perf|test|build|ci|chore|revert|release)(?:\(.+\))?:

[nrfulton]

Looks good, except for the failing ruff prec-commit hook.

Please run the pre-commit hooks and push ruff's changes. I'll then approve and merge.

Thanks for the contribution!

[psschwei]

Please run the pre-commit hooks and push ruff's changes

done!