A merged route that forgets the parseAggregate check silently returns one
backend's rows: an aggregate row carries no certname, hash or name, so the
identity-keyed merges collapse every backend's numbers into one. That is how
/facts/<name> shipped broken.
- Resolve every /pdb/query/v4 request through one route table
- Sum extract/function queries in handleQuery, before any route's handler runs
- Make each route that is not summed name its reason; the zero value is guarded
- Assert the guard over the route table, so a new route inherits the assertion
unkin-agent