Remove the no-op --collection option from get and get-thumb (closes #241)

Both commands listed `--collection <id>` as accepted and ignored. It now
is refused as an unknown option, and the README no longer mentions it.

Model: opus-5-5

README.md

@@ -31,8 +31,7 @@ again on the next run. Every download is decrypted on its way to disk.
 
 ## Getting Started
 
-The commands below need `git`, `yarn` and Node 22.13 or later. Node 23 needs
-23.5 or later.
+The commands below need `git`, Node 22 or later and `yarn`.
 
 ```bash
 git clone https://git.eeqj.de/sneak/quak.git
@@ -70,29 +69,11 @@ The library keeps a local copy of the account's album and file lists, the cache.
 It brings the cache up to date with the server in rounds called refreshes.
 
 quak is not published to a package registry: `package.json` marks it `private`,
-and `dist/` is not committed. Clone and build it as above, then link the clone
-into your own program:
-
-```bash
-# In the quak clone:
-yarn link
-
-# In your program's directory:
-yarn link quak
-```
-
-`yarn link` also installs the `quak` command in yarn's global bin directory, and
-`yarn unlink` in the clone removes the link and the command.
-
-A linked quak uses the dependencies that `yarn install` put in the clone, at the
-versions in quak's `yarn.lock`. Avoid `yarn add file:../quak`: it resolves
-quak's dependencies again, and their newer releases can need a newer Node.
-`yarn link quak` does not add quak to your `package.json`, so run it again in
-each new checkout of your program.
-
-The package's `main`, `types` and `exports` fields point into `dist/`, so the
-clone must be built first. The package is an ES module only, so a CommonJS
-program cannot `require` it.
+and `dist/` is not committed. Clone and build it as above, then add the clone to
+your own program's `package.json` by its path, for example
+`yarn add file:../quak`. The package's `main`, `types` and `exports` fields
+point into `dist/`, so the clone must be built first. The package is an ES
+module only, so a CommonJS program cannot `require` it.
 
 ```ts
 import { Client, Library } from "quak";

package.json

@@ -12,7 +12,7 @@
     "private": true,
     "type": "module",
     "engines": {
-        "node": "^22.13.0 || >=23.5.0"
+        "node": ">=22"
     },
     "main": "./dist/src/index.js",
     "types": "./dist/src/index.d.ts",