quak files takes the collection ID as an optional argument (closes #211)

Mandatory arguments are positional, so `quak files` takes the collection ID as an optional argument and the `--collection` option is removed. With a collection ID it lists that collection's files. Without one it lists every file in the account, collection by collection, each file once: the library keeps a record of a file for each collection that holds it, and only the first collection's record is listed, so that collection is its `collectionID` in `--json`. The `--help` text, the README and `TODO.md` say so.

Model: opus-5-5

test/cli/bin.test.ts

@@ -1,6 +1,7 @@
 /**
- * Tests for the retry options `bin/quak.ts` loads the saved session with:
- * `quak backup` gets the unattended ones, every other command the default.
+ * Tests for the retry options `bin/quak.ts` loads the saved session with
+ * (`quak backup` gets the unattended ones, every other command the default),
+ * and for `quak files` taking its collection ID as an optional argument.
  *
  * Each test runs `bin/quak.ts`, as the smoke test does, with its session loader
  * replaced by one that records the options it is given and reports no session,
@@ -26,14 +27,19 @@ vi.mock("../../src/cli-session.js", () => ({
 const argv = process.argv;
 const dir = mkdtempSync(join(tmpdir(), "quak-bin-test-"));
 
-// Run `quak <args>` to completion. The "Not logged in" message and the exit
-// are swallowed.
-const quak = async (...args: string[]): Promise<void> => {
-    vi.spyOn(process.stderr, "write").mockImplementation(() => true);
+// Run `quak <args>` to completion and return what it wrote on stderr, which is
+// kept off the terminal. The exit is swallowed.
+const quak = async (...args: string[]): Promise<string> => {
+    let written = "";
+    vi.spyOn(process.stderr, "write").mockImplementation((text) => {
+        written += String(text);
+        return true;
+    });
     vi.spyOn(process, "exit").mockImplementation(() => undefined as never);
     process.argv = ["node", "quak", ...args];
     vi.resetModules();
     await import("../../bin/quak.js");
+    return written;
 };
 
 afterEach(() => {
@@ -69,3 +75,15 @@ describe("bin/quak.ts session loading", () => {
         expect(loaded).toEqual([undefined]);
     });
 });
+
+// The command line takes `files` with or without a collection ID, and the
+// command runs as far as its session check either way (issue #211).
+describe("bin/quak.ts files", () => {
+    it("runs without a collection ID", async () => {
+        expect(await quak("files")).toMatch(/^Not logged in/);
+    });
+
+    it("runs with a collection ID", async () => {
+        expect(await quak("files", "7")).toMatch(/^Not logged in/);
+    });
+});