Add per-package publish tasks to Taskfile

[talkasab]

Summary

Replace the current monolithic publish:pypi task with independent per-package publish tasks. The current all-at-once publisher was needed for the initial multi-package release but won't be needed going forward.

Tasks

• Add publish:oidm-common task
• Add publish:findingmodel task
• Add publish:anatomic-locations task
• Add publish:findingmodel-ai task
• Remove publish:pypi aggregate task
• Remove build:packages aggregate task (replace with per-package build as needed)

Details

Each task should: clean dist/, build the single package with uv build --package <name>, then publish with uv publish. Same pattern as the current publish:pypi but one package at a time.

oidm-maintenance is not published to PyPI (internal tooling only).

Context

Replaces the current publish:pypi and build:packages tasks which build/publish everything at once. Going forward, packages are versioned and released independently.