fix: a bare seedpass-js printed help and then reported a bogus error

exitOverride() makes commander throw for everything it would otherwise exit
on -- displaying help and its own usage errors included. The handler only
recognised two of its codes, so running `seedpass-js` with no arguments
printed the help and followed it with `error: (outputHelp)`, and unknown
commands had their message printed twice.

Any commander.* code is now commander's business: honour its exit code and
let it own the message. SeedPass's own errors still print as before.

Found by running the command.

Co-Authored-By: Claude Fable 5 <[email protected]>

js/packages/cli/test/cli.test.ts

@@ -434,6 +434,27 @@ describe("document import/export", () => {
   });
 });
 
+describe("exit behaviour", () => {
+  it("does not report help output as an error", async () => {
+    // exitOverride() makes commander throw when it prints help, so a bare
+    // invocation printed the help and then claimed to have failed with
+    // "(outputHelp)".
+    const out: string[] = [];
+    const err: string[] = [];
+    const io: ProgramIo = { out: (l) => out.push(l), err: (l) => err.push(l) };
+    let thrown: { code?: string; exitCode?: number } | undefined;
+    try {
+      await buildProgram(io).parseAsync(["node", "seedpass-js"]);
+    } catch (e) {
+      thrown = e as { code?: string; exitCode?: number };
+    }
+    // commander signals help with its own code; main.ts must treat any
+    // commander.* code as commander's business, not as a SeedPass error.
+    expect(thrown?.code).toMatch(/^commander\./);
+    expect(err.join("\n")).not.toContain("outputHelp");
+  });
+});
+
 describe("error messages", () => {
   it("explains a corrupt or foreign vault file instead of leaking a codec error", async () => {
     const dir = await mkdtemp(join(tmpdir(), "seedpass-corrupt-"));