quak helper fix-missing-thumbnails --file on an empty cache stops fetching collections once it finds every file (closes #223)

`helper fix-missing-thumbnails --file` used to wait for a refresh, which
on an empty cache fetched the files of every collection. It now finds the
named files through the new `freshFilesByID` in `src/cli-read.ts`, by the
rule `freshFile` follows. On an empty cache it reads the collection list,
then one collection's files at a time, and stores none of the collections
or file records it reads. It searches the most recently updated
collection first. So a file in several albums is still named after the
first of them that `Library.albums.list()` lists. `fixMissingThumbnails`
now takes the records the command found, and fetches each original
through `lib.originalOf()`.

Model: opus-5-5

README.md

@@ -689,14 +689,15 @@ request, and neither fetches any collection's files nor changes the cache.
 `files` with a collection ID asks for the same list, then for that one
 collection's files, and does not change the cache either. On an empty cache,
 `get` and `get-thumb` ask for the same list, then for one collection's files at
-a time, until they find the file. They store none of the collections or file
-records they read. The original or thumbnail they fetch is kept in the cache.
-Once the cache holds the account's collections, they wait for a refresh instead.
-The others wait for a refresh, and so does `files` without a collection ID. With
-an empty cache, as on a first run, that refresh fetches the files of every
-collection, one collection after another, and stores nothing until it has them
-all, which on a large account takes a while. Meanwhile the command logs a line
-on stderr for each collection whose files it has fetched, such as
+a time, until they find the file. `helper fix-missing-thumbnails --file` does
+the same until it finds every file it names. They store none of the collections
+or file records they read. The original or thumbnail they fetch is kept in the
+cache. Once the cache holds the account's collections, they wait for a refresh
+instead. The others wait for a refresh, and so does `files` without a collection
+ID. With an empty cache, as on a first run, that refresh fetches the files of
+every collection, one collection after another, and stores nothing until it has
+them all, which on a large account takes a while. Meanwhile the command logs a
+line on stderr for each collection whose files it has fetched, such as
 `Fetched the files of 3 of 120 collections`, with `--json` too; `backup` does
 the same while the refresh it starts with runs. stdout holds only the command's
 output. If that round-trip fails, the command prints the error on one line and
@@ -1192,7 +1193,8 @@ It answers with every live file in that collection that decrypts, in the
 server's order. `collection` is a record that `freshCollections()` returned. The
 method fetches no other collection's files and stores nothing. `quak files` with
 a collection ID uses it, and so do `quak get` and `quak get-thumb` on an empty
-cache.
+cache. `quak helper fix-missing-thumbnails --file` uses it on an empty cache
+too.
 
 An album or file in the server's answer that quak cannot decrypt, or whose
 metadata is not JSON, does not fail the refresh. The refresh leaves it out, an