fix(extraction): repair missing archives before manual retry

Persist selected manual extraction repair requests, re-download only missing multipart members, and resume extraction after successful repairs across Stop, failures, and application restarts.

Allow complete archive sets and missing sets from the same package to progress together, preserve existing parts, and keep retry generations and run contexts isolated after failed repair downloads.

Expose direct child retries for persisted repair items and validate repair state through storage normalization and renderer deltas.

tests/storage.test.ts

@@ -1498,8 +1498,10 @@ describe("settings storage", () => {
       status: "downloading",
       itemIds: ["item1", "item2", "item3", "item4"],
       cancelled: false,
-      enabled: true,
-      downloadStartedAt: 0,
+      enabled: true,
+      manualExtractionPending: true,
+      manualExtractionRepairItemIds: ["item1", "missing-item", "item1"],
+      downloadStartedAt: 0,
       downloadCompletedAt: 0,
       createdAt: Date.now(),
       updatedAt: Date.now()
@@ -1595,8 +1597,10 @@ describe("settings storage", () => {
     expect(loaded.items["item3"].status).toBe("completed");
     expect(loaded.items["item4"].status).toBe("queued");
     expect(loaded.items["item1"].downloadedBytes).toBe(5000);
-    expect(loaded.packages["pkg1"].name).toBe("Test Package");
-  });
+    expect(loaded.packages["pkg1"].name).toBe("Test Package");
+    expect(loaded.packages["pkg1"].manualExtractionPending).toBe(true);
+    expect(loaded.packages["pkg1"].manualExtractionRepairItemIds).toEqual(["item1"]);
+  });
 
   it("preserves cleaned package progress aggregates while normalizing a session", () => {
     const session = emptySession();