Fix wheel and sdist build configuration

[mwojtyczka]

Summary

Build artifacts is broken after switching from hatch to uv: the wheel is coming out empty, and the sdist is unpacked into a src/ directory instead of a clean project layout.

Split the Hatch config into per-target sections:

• [tool.hatch.build.targets.wheel] — sets packages = ["src/databricks"] so the databricks.labs.blueprint package is actually included in the wheel.
• [tool.hatch.build.targets.sdist] — uses only-include = ["src", "README.md", "LICENSE", "NOTICE"] so the sdist contains the source tree and metadata at the top level.

Test plan

• uv build produces a non-empty wheel containing databricks/labs/blueprint/...
• sdist unpacks with src/, README.md, LICENSE, NOTICE at the top level
• pip install the wheel in a fresh venv and import databricks.labs.blueprint succeeds

[github-actions]

✅ 40/40 passed, 2 skipped, 1m58s total

_{Running from acceptance #433}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.15%. Comparing base (51e52cd) to head (e2537fb).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #377   +/-   ##
=======================================
  Coverage   80.15%   80.15%           
=======================================
  Files          17       17           
  Lines        2474     2474           
  Branches      403      403           
=======================================
  Hits         1983     1983           
  Misses        364      364           
  Partials      127      127           

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[asnare]

Thanks for flagging the problem. It took me a while to get back to this, and indeed it was a coincidence that it previously worked with hatch.