fix(cli): detect json mode for combined and =-form flags in error handler

`handleCliError` picked the error output format with a `--json`/`-j`
substring-free includes check, missing `--json=...` and combined short
flags like `-jy`/`-yj`. A parse-time ValidationError in those invocations
printed the human-readable ANSI error instead of the structured
VALIDATION_ERROR envelope. Broaden detection to a parse-free heuristic
matching `--json`, `--json=...`, `-j`, and combined short flags containing
`j`. Adds a `-jy` envelope test case.

Author: tcerqueira

main.ts

@@ -57,9 +57,7 @@ function handleCliError(e: unknown): never {
   const context: GlobalContext = {
     debug: Deno.args.includes("--debug"),
     endpoint: "",
-    json: Deno.args.includes("--json") || Deno.args.includes("-j")
-      ? true
-      : undefined,
+    json: Deno.args.some(isJsonModeArg) ? true : undefined,
   };
 
   if (e instanceof ValidationError) {
@@ -72,6 +70,16 @@ function handleCliError(e: unknown): never {
   error(context, e instanceof Error ? e.message : String(e));
 }
 
+/**
+ * Best-effort `--json` detection without a parsed context, used by
+ * `handleCliError` to pick the error output format when `parse()` itself throws.
+ * Matches `--json`, `--json=...`, `-j`, and combined short flags like `-jy`.
+ */
+function isJsonModeArg(arg: string): boolean {
+  return arg === "-j" || arg === "--json" || arg.startsWith("--json=") ||
+    /^-[a-z]*j[a-z]*$/.test(arg);
+}
+
 export function createSwitchCommand(
   handleApp: boolean,
 ): Command<GlobalContext> {

tests/cli_contract.test.ts

@@ -43,6 +43,16 @@ Deno.test("unknown flag with --json emits a USAGE envelope on stderr, clean stdo
   );
 });
 
+Deno.test("combined short flag -jy is detected as JSON mode for the error envelope", async () => {
+  // `-jy` bundles `-j` (json) and `-y` (non-interactive); a bad flag must still
+  // surface the structured envelope on stderr, not the human-readable error.
+  const res = await runCli(["-jy", "--does-not-exist"]);
+  assertEquals(res.code, 2, `stderr: ${res.stderr}`);
+  assertEquals(res.stdout.trim(), "", `stdout should be empty: ${res.stdout}`);
+  const envelope = JSON.parse(res.stderr.trim().split("\n").pop()!);
+  assertEquals(envelope.error.code, "VALIDATION_ERROR");
+});
+
 Deno.test("--help exits 0", async () => {
   const res = await runCli(["--help"]);
   assertEquals(res.code, 0, `stderr: ${res.stderr}`);