feat(ql3): establish 3.0 incubation baseline

back/runtime/ports/localArtifactCapacityProbe.ts

@@ -0,0 +1,12 @@
+export interface LocalArtifactCapacitySnapshot {
+  availableBytes: bigint;
+  totalBytes: bigint;
+}
+
+export interface LocalArtifactCapacityProbe {
+  inspect(root: string): Promise<LocalArtifactCapacitySnapshot>;
+}
+
+export interface LocalArtifactCapacitySource {
+  inspect(): Promise<LocalArtifactCapacitySnapshot>;
+}