Required schema args not enforced: unresolved path params sent as literals

[MattDevy]

Bug

When a command has required path parameters (like cluster info's --target) but the user provides no input at all (no CLI flags, no stdin, no --input-file), the handler runs with parsed.input as undefined. The Zod validation step is skipped entirely, and the required {param} placeholder remains as a literal string in the URL sent to Elasticsearch.

Steps to reproduce

$ elastic es cluster info

Expected: Error message indicating --target is required.

Actual:

{
  "error": {
    "code": "transport_error",
    "status_code": 400,
    "body": {
      "error": {
        "type": "illegal_argument_exception",
        "reason": "request [/_info/{target}] contains unrecognized target: [{target}]"
      }
    }
  }
}

The literal {target} is sent in the URL path.

Root cause

src/factory.ts, in the cmd.action() handler:

1. Schema-derived args are registered with cmd.option() (optional), never cmd.requiredOption()
2. When no input is provided at all, inputValue remains undefined
3. The validation block (if (inputValue !== undefined) { ... safeParse ... }) is skipped
4. parsed.input stays undefined, and the handler runs
5. interpolatePath() in the request builder can't substitute {target} because input is undefined, and arg.required is true so the optional-path-stripping branch doesn't apply

Suggested fix

Options:

1. Register required schema args with cmd.requiredOption() instead of cmd.option() so Commander enforces them before the handler runs
2. Run Zod validation even when inputValue is undefined: construct a minimal input from CLI args (even if empty) and validate it to catch missing required fields
3. In interpolatePath(), check for unresolved {param} placeholders after interpolation and throw a clear error

Option 2 is probably the most robust since it catches required body/query fields too, not just path params.