Fix: fail loudly on unknown CLI subcommands (#270)

Unknown/mistyped CLI subcommands now print 'Unknown command' and exit non-zero instead of silently routing to the detector. Closes #266. Version bump and changelog entry deferred (batching). Co-Authored-By: abdulwahabone

cli/bin/cli.js

@@ -10,13 +10,24 @@
  *   npx impeccable --help
  */
 
-import { readFileSync } from 'node:fs';
-import { join, dirname } from 'node:path';
+import { readFileSync, existsSync } from 'node:fs';
+import { join, dirname, resolve } from 'node:path';
 import { fileURLToPath } from 'node:url';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const SKILL_COMMANDS = new Set(['help', 'install', 'link', 'update', 'check']);
 
+// Is this a detect target (the `npx impeccable src/` shorthand) or a mistyped
+// command? Flags, URLs, path-shaped args, and real files/dirs (e.g. an
+// extension-less `Dockerfile`) are targets; anything else is an unknown command.
+function looksLikeDetectTarget(arg) {
+  const isFlag = arg.startsWith('-');
+  const isUrl = /^https?:\/\//i.test(arg);
+  const isPathShaped = arg.includes('/') || arg.includes('\\') || arg.includes('.');
+  const isExistingPath = existsSync(resolve(arg));
+  return isFlag || isUrl || isPathShaped || isExistingPath;
+}
+
 async function main() {
   const args = process.argv.slice(2);
   const command = args[0];
@@ -61,11 +72,16 @@ Compatibility:
   } else if (SKILL_COMMANDS.has(command)) {
     const { run } = await import('./commands/skills.mjs');
     await run(args);
-  } else {
+  } else if (looksLikeDetectTarget(command)) {
     // Default: treat as detect arguments (allow `npx impeccable src/` shorthand)
     process.argv = [process.argv[0], process.argv[1], ...args];
     const { detectCli } = await import('../engine/detect-antipatterns.mjs');
     await detectCli();
+  } else {
+    // An unknown bareword: a mistyped command (or an old cached version run
+    // against newer docs). Fail loudly instead of silently statting it as a path.
+    console.error(`Unknown command: "${command}"\n\nTo see a list of supported commands, run:\n  impeccable --help`);
+    process.exit(1);
   }
 }