Refresh before backup-metadata and the thumbnail helpers answer (closes #100)

backup-metadata, helper list-missing-thumbnails and helper
fix-missing-thumbnails now await lib.fresh() before reading the library,
as collections, files, get and get-thumb already do. A file added since
the cache was written is included, and a failed refresh is thrown, so
the CLI prints one line and exits 1 instead of answering from a stale
or empty cache. The README lists them among the commands that refresh
first.

Model: opus-5-5

src/cli-commands.ts

@@ -357,6 +357,9 @@ export const backupMetadataCommand = async (
     if (!client) return 1;
     const lib = await openReadLibrary(ctx, client);
     try {
+        // Refresh first so the dump holds current account state, not what the
+        // cache last held; a failed refresh throws.
+        await lib.fresh();
         const { failedMLBatches } = await runMetadataBackup(lib, client, dir, {
             exif: opts.exif || opts.all,
             onProgress: (msg) => ctx.stderr.write(msg + "\n"),
@@ -423,6 +426,9 @@ export const listMissingThumbnailsCommand = async (
     if (!client) return 1;
     const lib = await openReadLibrary(ctx, client);
     try {
+        // Refresh first so files added since the cache was written are
+        // checked; a failed refresh throws.
+        await lib.fresh();
         const missing = await listMissingThumbnails(lib, client, (msg) => {
             if (!opts.json) ctx.stderr.write(msg + "\n");
         });
@@ -458,6 +464,9 @@ export const fixMissingThumbnailsCommand = async (
     if (!client) return 1;
     const lib = await openReadLibrary(ctx, client);
     try {
+        // Refresh first so files added since the cache was written are found;
+        // a failed refresh throws.
+        await lib.fresh();
         let fileIDs: number[];
         if (opts.file && opts.file.length > 0) {
             fileIDs = opts.file.map(Number).filter(Number.isFinite);

src/metadata-backup.ts

@@ -140,8 +140,8 @@ const extractExif = async (
 // Dump every decrypted metadata layer the account holds into a directory tree
 // of plain JSON: account, per-collection, and per-file records including the
 // private and public magic metadata and (by default) the ML data. Collections
-// and files are enumerated from the library's cache rather than a fresh server
-// scan. Returns how many ML data requests failed; their files are still
+// and files are enumerated from the library's cache, which the caller refreshes
+// first. Returns how many ML data requests failed; their files are still
 // written, with `mlDataError` in place of `mlData`.
 export const runMetadataBackup = async (
     lib: Library,