fix: stop shipping empty top-level wherobots/__init__.py (0.28.1)

[ClayMav]

Summary

• Delete the empty wherobots/__init__.py from the dbapi source tree.
• Bump version 0.28.0 → 0.28.1.

The bug

Both wherobots-python-dbapi 0.28.0 and wherobots-python-sdk 0.2.0 claim ownership of wherobots/__init__.py:

• dbapi's was a 0-byte file (looks like an old setuptools leftover).
• sdk's is a 1.7 KB file that re-exports the public API (WherobotsJob, WherobotsConfig, enums, models, …).

When both wheels land in the same environment, whichever installs last wins. The default pip install wherobots-python-dbapi wherobots-python-sdk ordering puts dbapi last → its empty __init__.py overwrites sdk's → from wherobots import WherobotsJob raises ImportError. from wherobots.db import … keeps working in either order because submodule imports bypass the parent's __init__.py, so dbapi-only consumers (and airflow-providers-wherobots, which only uses wherobots.db.*) aren't affected.

The fix

Remove the empty file from dbapi's source. wherobots/ then becomes a PEP 420 implicit namespace package from dbapi's perspective; the Jobs SDK's __init__.py is the canonical one whenever both packages are installed. dbapi's exports live entirely under wherobots.db.*, which is unaffected.

Verified

Built the wheel locally and tested all three install orderings against wherobots-python-sdk==0.2.0 from PyPI:

Order	from wherobots import WherobotsJob	from wherobots.db import connect, Region
dbapi first, sdk second	✅	✅
sdk first, dbapi second	✅	✅
both in one pip install	✅	✅

Existing tests: 72/72 unit tests pass.

Repro of the bug on the current PyPI release (before this PR)

uv venv /tmp/v && VIRTUAL_ENV=/tmp/v uv pip install wherobots-python-dbapi==0.28.0 wherobots-python-sdk==0.2.0
cd /tmp && /tmp/v/bin/python -c "from wherobots import WherobotsJob"
# ImportError: cannot import name 'WherobotsJob' from 'wherobots'

Test plan

• CI green (lint + tests across 3.10–3.14)
• After merge + v0.28.1 tag, confirm pip index versions wherobots-python-dbapi shows 0.28.1 and the wheel contents no longer include wherobots/__init__.py
• Re-run the side-by-side install repro against the published 0.28.1