Store live photos as their image and their video (closes #107)

A live photo, which Ente stores as one ZIP, is unpacked as it downloads
into its image and its video, each `<fileID>.<ext>` with its extension
from the ZIP, beside `<fileID>.livephoto.json`, which names the two.
Both are checked against the recorded hash and renamed into place only
when both are complete. A ZIP with a second image or video, or whose
parts come to more than 20 times its size plus 16 MiB, is refused. The
backup and the content cache count a live photo as stored only with both
files, album folders link both, `quak get` writes both, and the content
result gives the video as `videoPath`. A ZIP an earlier version stored
is replaced.

Model: opus-5-5

src/cli-commands.ts

@@ -10,10 +10,11 @@ import {
     copyFileSync,
     existsSync,
     mkdirSync,
+    statSync,
     unlinkSync,
     writeFileSync,
 } from "node:fs";
-import { join } from "node:path";
+import { extname, join } from "node:path";
 import {
     type Client,
     type ClientSnapshot,
@@ -32,6 +33,7 @@ import {
     thumbnailName,
 } from "./cli-output.js";
 import { freshCollections, freshFiles, freshFile } from "./cli-read.js";
+import { withExtension } from "./filename.js";
 import { runMetadataBackup } from "./metadata-backup.js";
 import { listMissingThumbnails, fixMissingThumbnails } from "./thumbnails.js";
 
@@ -305,8 +307,29 @@ export const getCommand = async (
         // Default name is the file's own title, as the pre-library CLI used
         // (not the editedName-preferring projection title) (issue #52).
         const outPath = opts.out ?? originalName(file);
-        copyFileSync(result.path, outPath);
-        ctx.stderr.write(`${result.bytes} bytes -> ${outPath}\n`);
+        if (result.videoPath === undefined) {
+            copyFileSync(result.path, outPath);
+            ctx.stderr.write(`${result.bytes} bytes -> ${outPath}\n`);
+            return 0;
+        }
+        // A live photo is written as its image and its video, each named after
+        // the title with its own extension, as Ente's clients name them. With
+        // --out, the image goes there and the video beside it.
+        const imageOut =
+            opts.out ?? withExtension(outPath, extname(result.path));
+        const videoOut = withExtension(outPath, extname(result.videoPath));
+        if (imageOut.toLowerCase() === videoOut.toLowerCase()) {
+            ctx.stderr.write(
+                `File ${fileID} is a live photo, and its video would also be written to ${imageOut}\n`,
+            );
+            return 1;
+        }
+        copyFileSync(result.path, imageOut);
+        copyFileSync(result.videoPath, videoOut);
+        ctx.stderr.write(
+            `${result.bytes} bytes -> ${imageOut}\n` +
+                `${statSync(videoOut).size} bytes -> ${videoOut}\n`,
+        );
         return 0;
     } finally {
         await lib.close();