Release v1.1.1

CI/release pipeline now runs on Node.js 24-compatible GitHub Actions.
No user-visible behavior change; `DiffViewer.exe` is functionally
identical to v1.1.0.

This release also serves as the deferred `release.yml` smoke-test
for the action bumps (fix-forward path was chosen on #13; tagging
v1.1.1 verifies the workflow under the new actions).

AI-Local-Session: 005408cb-f6f7-4aa3-985e-71ff123cc4f8
AI-Cloud-Session: 8eab202e-51a1-4ca7-882c-132daec6adcf
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: geevensingh

CHANGELOG.md

@@ -12,6 +12,17 @@ body. Keep section headings exact and write notes in Markdown.
 
 ## [Unreleased]
 
+## [1.1.1] - 2026-05-18
+
+### Changed
+
+- CI/release pipeline now runs on Node.js 24-compatible GitHub
+  Actions (`actions/checkout@v6`, `actions/setup-dotnet@v5`,
+  `softprops/action-gh-release@v3`), ahead of the June 2 / Sep 16
+  2026 Node.js 20 deprecation deadlines. No user-visible behavior
+  change; the shipped `DiffViewer.exe` is functionally identical to
+  v1.1.0.
+
 ## [1.1.0] - 2026-05-18
 
 ### Added