test: pin version identity across pyproject / __version__ / CITATION.cff

[musharna]

Why

data-aggregator-mcp is the only repo in this account that pins version identity, via
tests/test_packaging.py. It earned its keep immediately — during today's v0.45.1 release
it caught two incomplete version bumps, one after the other.

The repos without it stayed green while carrying a stale version. That is the dangerous
part: absence of a test looks exactly like a passing one.

This repo was bitten by the citation half. CITATION.cff claimed 0.4.0 for a month while the project shipped 0.5.0, because nothing compared them.

What

tests/test_packaging.py, adapted to this repo's actual shape rather than copied:

• __version__ == pyproject.toml version
• CITATION.cff version == pyproject

No server.json assertions — this repo does not publish to the MCP registry, so the
data-aggregator version of the test does not apply verbatim.

tomli added to the dev extra for python_version < "3.11". tomllib is stdlib only
from 3.11 and this package supports >=3.9 with CI running 3.9 — an unguarded import tomllib would have failed collection on the two oldest legs. (That is not hypothetical: it
is exactly how the same port broke on ldraw-mcp, whose 3.10 leg went red before this was
caught.) Both import branches were exercised locally.

Verified in both directions

Run against a real editable install of this repo, then re-run with __version__ mutated,
so the test is known to fire on the condition it exists to catch:

as-is      2 passed
mutated    1 failed, 1 passed

🤖 Generated with Claude Code