Slice 11b backend addition for the orphan-resolution flow in the
/admin/rules UI. The Slice 10 fuzzy-match backfill (mig 089) staged
legacy paliad.deadlines rows the matcher could not bind to a unique
deadline_rule into paliad.deadline_rule_backfill_orphans. This adds
the two endpoints the editor needs to surface and resolve them:
GET /admin/api/orphans — unresolved staging rows,
hydrated with the candidate
rule rows in one round-trip.
POST /admin/api/orphans/{id}/resolve — picks a rule_id from the
candidate set, writes it onto
the deadline, and flips
resolved_at + resolved_rule_id
on the staging row in a single
tx.
The methods live on RuleEditorService because they share the same admin
surface and audit semantics; resolved_rule_id + resolved_at on the
staging row is the audit trail (mig 089 COMMENT). reason is captured
into paliad.audit_reason in the same tx so any future audit trigger on
paliad.deadlines picks it up automatically.
Typed errors:
ErrOrphanAlreadyResolved → 409 in handler
ErrOrphanCandidateMismatch → 400 in handler
Route ordering matches Slice 11a's pattern: the static path is
registered alongside the existing /admin/api/rules family inside the
adminGate block in handlers.go.
