Remove the content cache's handling of an earlier version's live-photo ZIP (closes #151)

quak keeps no handling of old data. The content cache no longer checks
whether a live photo's file with no JSON file naming it is a ZIP an
earlier version cached, and no longer removes it; such a file is left
alone, as any other one already was. The README sentences and the tests
about that ZIP are gone, and one download test no longer names it in its
title. How a live photo is stored and served today is unchanged.

Model: opus-5-5

test/library/content-library.test.ts

@@ -176,52 +176,6 @@ describe("Library content wiring", () => {
         await lib.close();
     });
 
-    it("removes a live photo's ZIP an earlier version cached when it opens, and precaches its image and video", async () => {
-        const { file: live, body } = await asLivePhoto(file(1, 1));
-        class LiveClient extends MockClient {
-            override async filesSince(): Promise<FilesPage> {
-                return { files: [live], deleted: [], cursor: 1 };
-            }
-        }
-        const originals = join(root, "cache", "originals");
-        const open = (opts: Partial<LibraryOptions>): Promise<Library> =>
-            Library.open({
-                client: new LiveClient(),
-                cacheDirectory: join(root, "cache"),
-                contentSource: cdnSource(new Map([[1, body]])),
-                refreshIntervalSeconds: 3600,
-                precacheThumbnails: false,
-                precacheOriginals: false,
-                ...opts,
-            });
-        // A first run records the library, so the next one knows that file 1
-        // is a live photo when it opens the cache.
-        await (await open({})).close();
-        writeFileSync(join(originals, "1.jpg"), livePhotoZip());
-
-        let precached!: () => void;
-        const done = new Promise<void>((r) => (precached = r));
-        const lib = await open({
-            precacheOriginals: true,
-            onProgress: (e) => {
-                if (e.operation === "precacheOriginals" && e.status === "done")
-                    precached();
-            },
-        });
-        expect(existsSync(join(originals, "1.jpg"))).toBe(false);
-        await done;
-
-        expect(readdirSync(originals).sort()).toEqual([
-            "1.heic",
-            "1.livephoto.json",
-            "1.mov",
-        ]);
-        expect(lib.photos.byID({ fileID: 1 })!.record().originalPath).toBe(
-            join(originals, "1.heic"),
-        );
-        await lib.close();
-    });
-
     it("throws from content methods when opened without a content source", async () => {
         const lib = await Library.open({
             client: new MockClient(),