feat(ql3): establish 3.0 incubation baseline

back/runtime/ports/runLostRetrySource.ts

@@ -0,0 +1,18 @@
+export const MAX_RUN_LOST_RETRY_PAGE_SIZE = 64;
+
+export interface RunLostRetryCandidate {
+  runId: string;
+  phase: 'lost' | 'retry_wait';
+  availableAtMs: number;
+}
+
+export interface ListRunLostRetryCandidatesOptions {
+  observedAtMs: number;
+  limit?: number;
+}
+
+export interface RunLostRetrySource {
+  listCandidates(
+    options: ListRunLostRetryCandidatesOptions,
+  ): Promise<readonly RunLostRetryCandidate[]>;
+}