feat: Barnevernet Analyzer — document analysis + partisan RAG brief

7-step agent pipeline: document classification, party extraction, timeline
extraction, corpus RAG (child_welfare/echr/family_core/bufdir_guidance),
and synthesis using the user's chosen engine (including dbn-legal-agent).
Progressive NDJSON streaming renders doc_meta, parties, and timeline cards
before the final advocacy brief and procedural red flags arrive.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/layout.php

@@ -13,6 +13,7 @@ $navItems = [
     'search'        => ['Search',        'Legal sources'],
     'deep-research' => ['Deep research', 'Agent + RAG'],
     'advocate'      => ['Advocate',      'Take a side'],
+    'barnevernet'   => ['BVJ Analyzer',  'Document'],
     'summarize'     => ['Summarize',     'Pasted text'],
     'timeline'      => ['Timeline',      'Events'],
     'redact'        => ['Redact',        'Privacy'],