test(e2e): expand archive format coverage (tar/tgz/7z/rar) (#720)

* test(e2e): expand archive coverage to tar/tgz/7z/rar

* test: address copilot archive fixture review feedback

* test(e2e): add rar smoke coverage and align archive deps

* test(e2e): make tgz fixture gzip header deterministic

* test(e2e): keep legacy zip temp dir ignored

* test(e2e): address remaining copilot review comments

* test(e2e): make 7z fixture generation deterministic and strict

* test(e2e): fail fast when sample.rar fixture is missing

.github/workflows/nightly-e2e.yml

@@ -36,10 +36,10 @@ jobs:
         with:
           python-version: '3.11'
 
-      - name: Install LibreOffice + zip
+      - name: Install LibreOffice + archive tools
         run: |
           sudo apt-get update
-          sudo apt-get install -y libreoffice zip
+          sudo apt-get install -y libreoffice zip p7zip-full
 
       - name: Setup Python deps for office fixtures
         run: |