feat: add Report/About/Changelog buttons to Support ribbon group

- REPORT opens GitHub new-issue page
- ABOUT opens a dialog window with version, OS and arch info + Copy Info button
- CHANGELOG opens GitHub releases page
- Fix Windows build: add windows-sys as target-specific dependency for PRINT command

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/icons/about.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round">
+  <!-- Circle -->
+  <circle cx="12" cy="12" r="9"/>
+  <!-- i dot -->
+  <circle cx="12" cy="8" r="0.8" fill="currentColor" stroke="none"/>
+  <!-- i stem -->
+  <line x1="12" y1="11" x2="12" y2="16"/>
+</svg>