fix(deb): broaden libicu Depends so .deb installs across Debian/Ubuntu

jpackage runs `dpkg-shlibdeps` against the bundled JDK runtime's native
libs (libfontmanager.so etc. link libicu) and pins Depends to the build
host's libicu version. CI builds on ubuntu-24.04, so the .deb requires
libicu74 — uninstallable on Ubuntu 22.04 (libicu70), Debian 12 (libicu72),
Debian 11 (libicu67), and Debian 13 (libicu76). Neither jpackage nor the
Compose Multiplatform DSL exposes a way to override the auto-generated
Depends.

Add scripts/relax-deb-libicu.sh which extracts the .deb with `dpkg-deb -R`,
rewrites `libicuNN` (or any alternation thereof) to
`libicu66 | libicu67 | libicu70 | libicu72 | libicu74 | libicu76 | libicu77`,
and repacks. The script is idempotent and a no-op for .debs without a
libicu Depends.

Wire it into both release legs (desktopApp + amy CLI) in
create-release.yml, and into the desktop test/build leg in build.yml so
testers downloading the CI artifact hit the same fix.

.github/workflows/build.yml

@@ -68,6 +68,16 @@ jobs:
       - name: Test + Build Desktop (gradle)
         run: ./gradlew :quartz:jvmTest :commons:jvmTest :nestsClient:jvmTest :cli:test :desktopApp:test :desktopApp:${{ matrix.desktop-task }} --no-daemon
 
+      # jpackage pins libicu to the build host's version (libicu74 on
+      # ubuntu-24.04). Rewrite the .deb so testers on other Debian/Ubuntu
+      # releases can install the uploaded artifact.
+      - name: Relax libicu dependency in .deb
+        if: matrix.desktop-task == 'packageDeb'
+        run: |
+          set -euo pipefail
+          chmod +x scripts/relax-deb-libicu.sh
+          scripts/relax-deb-libicu.sh desktopApp/build/compose/binaries/main/deb/*.deb
+
       - name: Upload Desktop Distribution
         uses: actions/upload-artifact@v7
         with: