fix: add corpora.json with UNHCR entry to git

annotation_data/corpora.json

@@ -0,0 +1,14 @@
+[
+    {
+        "id": "wbg",
+        "name": "World Bank",
+        "extractions_dir": "wbg_extractions",
+        "links_file": "wbg_data/wbg_pdf_links.json"
+    },
+    {
+        "id": "unhcr",
+        "name": "UNHCR",
+        "extractions_dir": "unhcr_extractions",
+        "links_file": "unhcr_data/unhcr_pdf_links.json"
+    }
+]