fix: Add impressum keywords to dsi_discovery.py inline DSI_KEYWORDS

The inline DSI_KEYWORDS in dsi_discovery.py was missing 'impressum'.
This caused self-extraction to skip impressum pages, returning
datenschutz text instead. Added: impressum, anbieterkennzeichnung,
imprint, legal notice, site notice.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

consent-tester/services/dsi_discovery.py

@@ -44,6 +44,10 @@ DSI_KEYWORDS: dict[str, list[str]] = {
         "widerruf", "rücktrittsrecht",
         # Cookie
         "cookie-richtlinie", "cookie-policy", "cookie-hinweis",
+        # Impressum
+        "impressum", "anbieterkennzeichnung",
+        # Imprint (EN)
+        "imprint", "legal notice", "site notice",
     ],
     "en": [
         "privacy policy", "privacy notice", "data protection", "data policy",