fix: add libicu74 to Docker image + invariant mode workaround for bake

libicu74 missing from Ubuntu 24.04 image causes dotnet/Firely.Terminal to
fail with ICU error when bake=true in container_mode.
- Dockerfile: add libicu74 (proper fix after Docker rebuild)
- action.yml: set DOTNET_SYSTEM_GLOBALIZATION_INVARIANT=1 in container_mode
  as immediate workaround until the new image is live

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

Author: nriss

Dockerfile

@@ -21,6 +21,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     ruby-bundler \
     build-essential \
     openjdk-17-jdk-headless \
+    libicu74 \
     locales \
     && locale-gen en_US.UTF-8 \
     && rm -rf /var/lib/apt/lists/*

action.yml

@@ -84,6 +84,9 @@ runs:
       - name: firely
         if: ${{ inputs.bake == 'true' }}
         shell: bash
+        env:
+          # libicu absent de l'image Docker (Ubuntu 24.04) — invariant mode requis jusqu'au prochain rebuild
+          DOTNET_SYSTEM_GLOBALIZATION_INVARIANT: ${{ inputs.container_mode == 'true' && '1' || '0' }}
         run: dotnet tool install --global Firely.Terminal --version 3.0.0
 
       # Verif de la configuration pour la méthode bake