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/create-release.yml

@@ -103,6 +103,15 @@ jobs:
           timeout_minutes: 15
           command: ./gradlew --no-daemon :desktopApp:${{ matrix.tasks }}
 
+      # jpackage pins libicu to the build host's version (libicu74 on
+      # ubuntu-24.04). Rewrite the .deb so it installs across Debian/Ubuntu.
+      - name: Relax libicu dependency in .deb
+        if: matrix.family == 'linux'
+        run: |
+          set -euo pipefail
+          chmod +x scripts/relax-deb-libicu.sh
+          scripts/relax-deb-libicu.sh desktopApp/build/compose/binaries/main-release/deb/*.deb
+
       - name: Build portable archives (windows + linux-portable)
         if: matrix.family == 'windows' || matrix.family == 'linux-portable'
         run: |
@@ -248,6 +257,15 @@ jobs:
           timeout_minutes: 15
           command: ./gradlew --no-daemon :cli:${{ matrix.tasks }}
 
+      # jpackage pins libicu to the build host's version (libicu74 on
+      # ubuntu-24.04). Rewrite the .deb so it installs across Debian/Ubuntu.
+      - name: Relax libicu dependency in .deb
+        if: matrix.family == 'linux'
+        run: |
+          set -euo pipefail
+          chmod +x scripts/relax-deb-libicu.sh
+          scripts/relax-deb-libicu.sh cli/build/jpackage/*.deb
+
       - name: Collect + rename assets
         run: |
           set -euo pipefail