detect_shadowed_dcode

Return the shadowing dcode entry point on the user's PATH, if any.

After a successful uv tool upgrade, the upgraded binary only takes effect on the next manual launch if the user's PATH resolves to uv's tool bin dir for dcode (and deepagents-code) — or to a link into it, which the resolved-target check below also accepts. A pre-uv install earlier on PATH will silently win and report the old version, which looks like "the upgrade didn't work" to the user.

This compares each supported console script against uv's tool bin dir. A mismatch means a different binary will run the next time the user launches that entry point themselves.

The primary comparison is between directories rather than resolved symlink targets (see the inline note below for why), but a directory mismatch alone would misreport a dcode symlink that lives in an unrelated bin dir and points into the upgraded tool venv (e.g. a manually-created convenience symlink, or a package manager that re-exposes uv's shim). Those launches do run the upgraded entry point, so a second check compares resolved targets before reporting a conflict.