Add My Docs picker to deep-research, advocate, barnevernet, korrespond, citations

- PHP: Add docPickerSection (button + chips + hidden input) to all 5 tool pages
- JS: Send doc_ids in payload for deep-research, advocate, barnevernet, korrespond
- Backend: Inject selected corpus doc content into paste_text/narrative/notes via dbnToolsInjectDocContent
- Citations: Add upload zone (file → api/extract.php → textarea) + paste textarea with live Norwegian legal reference extraction (regex) + ref chips → title search; doc picker populates titleInput via MutationObserver

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

assets/js/deep-research.js

@@ -325,6 +325,8 @@
       language: lang,
       controls: getControls(),
     };
+    const _drDocIds = (document.getElementById('docPickerIds')?.value || '').split(',').map(Number).filter(Boolean);
+    if (_drDocIds.length) payload.doc_ids = _drDocIds;
     if (branchContext) {
       payload.prior_context = branchContext;
       payload.branch_notes = (els.branchNotes ? els.branchNotes.value : '').trim();