chore(release): bump version to 0.40.0

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

packaging/release-notes.md.tmpl

@@ -3,6 +3,7 @@
 Notebook app for pen, touch and mouse on Linux (tested on Zorin OS 18 / Ubuntu 24.04).
 
 ### Highlights:
+- **Android**: `ink-notes_<version>_arm64.apk` brings ink-notes to Android 8 and newer (64-bit ARM) – download it on the device and open it to install. The pen is told apart from fingers (pressure, pen buttons, eraser end, palm rejection), text fields open the soft keyboard, import and inserting images use the system file dialog, and exports are saved to `Download/ink-notes` (Android 10 and newer). Notebooks live in the app's own storage and are removed when uninstalling; updates are installed by opening the new APK. Nothing changes on Linux and Windows
 - **Battery drain fixed**: ink-notes redrew its window at full frame rate even when nothing happened, which kept the app and the desktop (e.g. gnome-shell) busy and drained the battery. It now only draws when something changes; idle CPU load drops to practically zero. Also applies to Windows. Internally, the Android version now follows the app lifecycle and can be packed into an APK (not part of the release yet)
 - **PDF export on current lopdf**: The PDF export uses its own small PDF writer on top of lopdf 0.46 instead of the outdated printpdf 0.7 (which pinned lopdf 0.31). Exported PDFs look the same – layers, searchable text, images, highlighters and bookmarks stay as before
 - **Windows mouse fix**: The mouse works normally again in the Windows version – Windows Ink reported it as a pen, so clicks and moves went the wrong way. Nothing changes on Linux