fix(cli): name the removed setup flags instead of a generic unknown-flag error

[Agnik47]

Problem

#493 removed --mode and --api-key from webcmd setup. Both now fall through to the generic unknown-flag branch:

$ webcmd setup --mode local --browser cloak
ok: false
error:
  code: ARGUMENT
  message: unknown flag --mode for `setup`
  help: >-
    valid flags for `setup`: --browser, --chrome-profile, --import-chrome-cookies,
    --no-import-chrome-cookies, --sync-to-chrome, --status, --help
  exitCode: 2

That message can't tell the user whether they mistyped something or the flag is gone, and it doesn't point at --browser, which is what replaced --mode local. webcmd setup --mode local --browser ... was the documented form until recently, so it is still in older docs, in blog posts, and in muscle memory.

Change

parseSetupArgs now names removed flags before the generic branch:

$ webcmd setup --mode local --browser cloak
ok: false
error:
  code: ARGUMENT
  message: >-
    `setup` no longer accepts --mode; setup always configures local mode, so drop the
    flag and pick a browser with `webcmd setup --browser <cloak|chrome|slab|absolute-path>`.
  exitCode: 2

$ webcmd setup --api-key sk-...
  message: '`setup` no longer accepts --api-key; setup no longer stores a Webcmd Cloud API key.'

Handles the --flag value and --flag=value spellings. Genuinely unknown flags (--bogus) keep the existing "unknown flag" message and valid-flag list, and SETUP_HELP is unchanged — removed flags are named on use, not advertised.

Tests

Added a parameterized case in src/hosted/setup.test.ts covering --mode local, --mode=local, and --api-key, asserting each is named and no longer reaches the unknown-flag branch.

src/hosted/setup.test.ts: 49/49 pass. tsc --noEmit: clean.

Notes

I originally had docs changes alongside this — the setup --mode local --browser ... occurrences in cli-reference.mdx / troubleshooting.mdx. Those are already fixed on main, so this PR is the CLI-side half only.

[github-actions]

🟢 No documentation gap found — medium confidence

The automated review found no documentation gap in the supplied changes.

This review is advisory and does not block merging.