1.0.0

The version, the changelog entry, the plan and the README. Nothing else,
which is what makes this readable as a release rather than as work.

CHANGELOG.md's 1.0.0 entry is assembled from every version below it, as
that file has said it would be since it was written: those shipped as a
running deployment rather than as releases, and this is what they add up
to. It is also what an administrator reads -- /admin/updates takes release
notes out of the annotated tag, so the tag message is this entry.

It says what arrived, then the part worth reading: the nine things that
had shipped looking correct and were found by five audit passes. Then
where the edges are, because a first release should say what it does not
do before somebody finds out.

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

README.md

@@ -8,6 +8,7 @@
 </p>
 
 <p align="center">
+  <img alt="Version 1.0.0" src="https://img.shields.io/badge/version-1.0.0-6B8E4E?style=flat-square">
   <img alt="Python 3.11+" src="https://img.shields.io/badge/python-3.11%2B-3E6B7A?style=flat-square">
   <img alt="License GPL-3.0" src="https://img.shields.io/badge/license-GPL--3.0-C9A227?style=flat-square">
   <img alt="No Node required" src="https://img.shields.io/badge/build%20step-none-6B8E4E?style=flat-square">