`CodeGraph#enrich` function name matching is too fuzzy

[malandrina]

Description

I noticed nuanced enrich matches function names less precisely than it ought to.

Steps to reproduce:

% git clone git@github.com:pallets/flask.git
% cd flask
% uv tool install nuanced
% nuanced init .
% nuanced enrich src/flask/app.py dispatch_request

Expected behavior: Graph fragment for src.flask.app.Flask.dispatch_request is returned

Actual behavior: Error message is returned 👇

Multiple definitions for dispatch_request found in src/flask/app.py: src.flask.app.Flask.dispatch_request, src.flask.app.Flask.full_dispatch_request

We should update CodeGraph#enrich to match function names more precisely. Relevant code: https://github.com/nuanced-dev/nuanced/blob/main/src/nuanced/code_graph.py#L95