chore(release): bump to 5.11.1

5.11.0 ships from the base commit before this branch lands, so the
reference cleanup and its hygiene check go out as 5.11.1: plugin.json,
package.json, package-lock.json (both fields), the README badge and a new
CHANGELOG entry. No tag.

Suite after staging: 1240 tests, 1238 pass, 0 fail, 2 skipped;
verify.sh 7 pass, 0 fail.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -4,6 +4,26 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## v5.11.1 — 2026-09-23 — dead references to a retired repository removed
+
+### Changed
+
+- The annotation surface's provenance is described as the pattern it follows
+  (pencil toggle, intent buttons, popover form, structured export) instead of
+  by naming a repository that no longer exists: `.claude-plugin/plugin.json`
+  and `package.json` descriptions, `README.md`, `docs/architecture.md`, the
+  v5.0.3 entry below, and two comments in `scripts/annotate.mjs` and
+  `tests/scripts/annotate.test.mjs`. No behavior change.
+
+### Added
+
+- `tests/lib/retired-references.test.mjs` fails when any tracked text file or
+  path contains a term from the gitignored local list
+  `tests/.excluded-terms.local.txt`. The scanner is validated against a planted
+  known-positive, an empty scan fails closed, and the named exemption list is
+  empty and rot-checked. Without the local list the scan is skipped with an
+  explicit message.
+
 ## v5.11.0 — 2026-09-23 — /trekplan plans only against an approved intent
 
 ### Added