A version that was not two spellings of itself

The Updates page read "v1.0.0 (reports 1.0.0)". That note exists to warn
that a tag was cut before the version bump -- a release nobody can
identify afterwards -- and it was firing on two ways of writing one
version, because `git describe` answers with the tag's name and tags here
carry a `v`.

Stripped in `_describe`, where `resolve_target` has always stripped it and
where the docstring already promised the stripped form. The mismatch check
then compares two things spelled the same way, and still reports a tag
that really does disagree; there is a test for each half.

Found by cutting the first release, which is the only place it could have
been found.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -16,6 +16,14 @@ for 1.0.0 have something to be assembled from.
 
 ## Unreleased
 
+## 1.0.1
+
+- Fixed: the Updates page showed **"v1.0.0 (reports 1.0.0)"** — two spellings of
+  one version, in a note whose whole purpose is to warn that a tag was cut
+  before the version bump. `git describe` answers with the tag's name, and tags
+  here carry a `v`. Found by cutting the first release, which is the only place
+  it could have been.
+
 ## 1.0.0
 
 The first release. Every version before it shipped as a running deployment