feat(action): add composite action for generating Debian changelog

- Introduces a composite GitHub Action to automate the generation of
  Debian-compatible changelogs using git-cliff.
- Provides configurable inputs for tag, package details, author info,
  and output file.
- Includes default configurations and scripts for installation and
  changelog generation.

action.yml

@@ -0,0 +1,52 @@
+name: Auto Debian Package Changelog Generation
+description: "One-stop composite action for generating a Debian-compatible changelog using git-cliff"
+
+inputs:
+  tag:
+    description: "Git tag"
+    required: true
+  package_name:
+    description: "Package name"
+    required: true
+  author_name:
+    description: "Package author name"
+    required: true
+  author_email:
+    description: "Package author email"
+    required: true
+  output_file:
+    description: "Output file for the changelog"
+    required: false
+    default: "debian/changelog"
+  cliff_config:
+    description: "Path to the Git-Cliff configuration file"
+    required: false
+    default: ""
+
+runs:
+  using: "composite"
+  steps:
+    # 1) Install git-cliff (latest, default arch)
+    - name: Install git-cliff
+      shell: bash
+      run: |
+        bash "${{ github.action_path }}/scripts/install-git-cliff.sh"
+
+    # 2) Generate changelog
+    - name: Generate Debian changelog
+      shell: bash
+      env:
+        PACKAGE_NAME: ${{ inputs.package_name }}
+        AUTHOR_NAME: ${{ inputs.author_name }}
+        AUTHOR_EMAIL: ${{ inputs.author_email }}
+      run: |
+        # Select config: user-provided or default within the action
+        CONFIG_PATH="${{ inputs.cliff_config }}"
+        if [[ -z "$CONFIG_PATH" ]]; then
+          CONFIG_PATH="${{ github.action_path }}/configs/cliff.debian.toml"
+        fi
+
+        bash "${{ github.action_path }}/scripts/generate-changelog.sh" \
+          -c "$CONFIG_PATH" \
+          -t "${{ inputs.tag }}" \
+          -o "${{ inputs.output_file }}"