feat(overlay): add in-app changelog modal

- Add a changelog modal opened from tray "View Changelog" or the update notification's "What's New" button; renders in-player or in its own window like the help modal
- Fetch changelog from the newest published release so newer-than-installed notes are visible, falling back to the bundled CHANGELOG.md on failure
- Group versions by minor line (current expanded, older folded), badge the installed version, tag newer ones "New"
- Support J/K/arrow navigation, Enter to fold/unfold, R to refetch, Esc to close
- Add changelog parsing/semver-compare utils and changelog IPC channel/runtime; bundle CHANGELOG.md into packaged builds
- Replace release/release-notes.md with changes/changelog-modal.md changeset entry

package.json

@@ -260,6 +260,10 @@
       {
         "from": "dist/launcher/subminer",
         "to": "launcher/subminer"
+      },
+      {
+        "from": "CHANGELOG.md",
+        "to": "CHANGELOG.md"
       }
     ]
   },