Stop one malformed call document 500ing the whole debug view

/admin/debug/correlation built its call lookup as {doc["call_id"]: doc}, which
raises KeyError on any stored call missing that field -- and at least one in
production is missing it. One bad document took down the entire view rather
than dropping a single call from it.

The document id is authoritative and always present; the call_id *field* is
written by the upload path and evidently has not always been. Keying off the id
we asked for removes the dependency on the field entirely.

Found while generating a correlation dump server-side, because the UI route this
serves has been unusable tonight.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

drb-c2-core/app/routers/admin.py

@@ -129,7 +129,14 @@ async def debug_correlation(
     unique_call_ids = list(dict.fromkeys(all_call_ids))  # dedupe, preserve order
 
     call_docs = await asyncio.gather(*(fstore.doc_get("calls", cid) for cid in unique_call_ids))
-    call_map: dict[str, dict] = {doc["call_id"]: doc for doc in call_docs if doc}
+    # Key off the id we asked for, not doc["call_id"]. At least one stored call
+    # has no call_id field -- the document id is authoritative and always
+    # present, while the field is written by the upload path and evidently was
+    # not always there. Indexing the field raised KeyError and took the whole
+    # debug view down with a 500 over a single malformed document.
+    call_map: dict[str, dict] = {
+        cid: doc for cid, doc in zip(unique_call_ids, call_docs) if doc
+    }
 
     # ── Build incident debug records ──────────────────────────────────────────
     incident_records = []