Q128: every model call of a run is recorded with its purpose and listed in the run

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main/database/migrations/091-request-purpose.ts

@@ -0,0 +1,8 @@
+// Requests from before purposes were recorded stay 'unrecorded' rather than being guessed.
+export const requestPurposeSchema = `
+  alter table provider_requests add column purpose text not null default 'unrecorded';
+  create index if not exists provider_requests_run on provider_requests(task_run_id);
+
+  insert into schema_migrations(version, name, applied_at)
+  values (91, 'request_purpose', datetime('now'));
+`;