feat: 4 remaining tasks — EU institutions, banner integration, JS-sites, Caritas fixes

1. EU Institution Checks (Verordnung 2018/1725):
   - New doc_type "eu_institution" with 9 L1 + 15 L2 checks
   - Both German + English patterns (EU institutions are multilingual)
   - Auto-detection via "2018/1725", "EDSB", "EDPS" keywords
   - Correct article references (Art. 15 instead of 13, Art. 5 instead of 6)

2. Banner Check Integration:
   - banner_runner.py maps scan results to 36 L1/L2 structured checks
   - BannerCheckTab shows hierarchical ChecklistView with hints
   - 3-phase summary (cookies/scripts before/after consent)
   - /scan endpoint now includes structured_checks in response

3. JS-heavy Website Fixes (dm, Zalando, HWK):
   - dsi_helpers.py: goto_resilient (networkidle→domcontentloaded fallback)
   - try_dismiss_consent_banner before text extraction
   - PDF redirect detection (dm.de redirects to GCS PDF)

4. Caritas False Positive Fixes:
   - Phone regex allows parentheses: +49 (0)761 → now matches
   - "Recht auf Widerspruch" (3 words) + §23 KDG → matches Art. 21
   - Church authorities: "Katholisches Datenschutzzentrum" recognized

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

backend-compliance/compliance/services/doc_checks/__init__.py

@@ -2,7 +2,7 @@
 doc_checks — Legal document compliance checkers.
 
 Provides checklists and functions for verifying legal documents
-(DSI, AGB, Impressum, Cookie, Widerruf, Social Media, DSFA)
+(DSI, AGB, Impressum, Cookie, Widerruf, Social Media, DSFA, EU Institution)
 against their mandatory content requirements.
 
 Two check levels:
@@ -18,6 +18,7 @@ from .impressum_checks import IMPRESSUM_CHECKLIST
 from .cookie_checks import COOKIE_CHECKLIST
 from .social_media_checks import JOINT_CONTROLLER_CHECKLIST
 from .dsfa_checks import DSFA_CHECKLIST
+from .eu_institution_checks import EU_INSTITUTION_CHECKLIST
 
 __all__ = [
     "check_document_completeness",
@@ -29,4 +30,5 @@ __all__ = [
     "COOKIE_CHECKLIST",
     "JOINT_CONTROLLER_CHECKLIST",
     "DSFA_CHECKLIST",
+    "EU_INSTITUTION_CHECKLIST",
 ]