fix(landing-page): diagram links - use bundle path, not docs/diagrams/

Architecture diagram links on the deployed landing page returned 404
because the generator emitted 'docs/diagrams/<file>.svg' (repo-relative)
while validate.yml/release.yml deploy the SVGs to '<bundle>/diagrams/'.

Use the same bundle-relative pattern as coverage/cppcheck/traceability
(emit just 'diagrams/<file>.svg').

Also translates two remaining German comments in release.yml
('CI-generierte Artefakte', 'Source-Code zum Anklicken...').

tools/generate_landing_page.py

@@ -228,12 +228,12 @@ footer {{ text-align: center; color: #888; padding: 30px; font-size: 13px; }}
                               "Machine-readable format for your own tools")
     html_body += "</ul></section>"
 
-    # Diagrams
+    # Diagrams (bundle layout: SVGs are at <bundle>/diagrams/, not docs/diagrams/)
     diagrams = sorted((REPO / "docs" / "diagrams").glob("*.svg"))
     if diagrams:
         html_body += "<section><h2>Architecture Diagrams (PlantUML)</h2><ul>"
         for d in diagrams:
-            href = os.path.relpath(d, REPO)
+            href = f"diagrams/{d.name}"
             html_body += f"  <li><a href='{html.escape(href)}'>{html.escape(d.stem)}</a></li>\n"
         html_body += "</ul></section>"