refactor: make API registry authoritative

backend/http/context.py

@@ -0,0 +1,12 @@
+from __future__ import annotations
+
+import re
+import uuid
+
+
+REQUEST_ID_PATTERN = re.compile(r"[A-Za-z0-9._-]{8,80}")
+
+
+def correlation_id(supplied: str = "") -> str:
+    value = str(supplied or "").strip()
+    return value if REQUEST_ID_PATTERN.fullmatch(value) else uuid.uuid4().hex