feat: add CLI entry point for Python skills to call via subprocess

Adds src/cli.ts with commands: token, session, client-config, request.
Python auth-runtime-py will call this via `bun run cli.ts` instead of
reimplementing auth logic in Python.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli.ts

@@ -0,0 +1,110 @@
+#!/usr/bin/env bun
+/**
+ * CLI entry point for auth-runtime.
+ *
+ * Commands:
+ *   token                              → {"token":"st_xxx"}
+ *   session                            → {"accessToken":"...","expiresIn":900}
+ *   client-config                      → {"clientId":"...","metadata":{...}}
+ *   request <METHOD> <path> [options]  → {"status":200,"body":"..."}
+ *
+ * Options for `request`:
+ *   --body '{"key":"value"}'   Request body (JSON string)
+ *   --api-base URL             Override API base URL
+ *
+ * JSON output to stdout, errors to stderr, exit code 0/1.
+ */
+
+import { createSkillClient } from './index.js';
+
+function fatal(msg: string): never {
+  console.error(msg);
+  process.exit(1);
+}
+
+function usage(): never {
+  fatal(
+    'Usage:\n' +
+    '  auth-rt token\n' +
+    '  auth-rt session\n' +
+    '  auth-rt client-config\n' +
+    '  auth-rt request <METHOD> <path> [--body JSON] [--api-base URL]',
+  );
+}
+
+async function main() {
+  const args = process.argv.slice(2);
+  if (args.length === 0) usage();
+
+  const command = args[0];
+
+  if (command === 'token') {
+    const client = createSkillClient();
+    const session = await client.session();
+    console.log(JSON.stringify({ token: session.accessToken }));
+    return;
+  }
+
+  if (command === 'session') {
+    const client = createSkillClient();
+    const session = await client.session();
+    console.log(JSON.stringify(session));
+    return;
+  }
+
+  if (command === 'client-config') {
+    const client = createSkillClient();
+    const config = await client.clientConfig();
+    console.log(JSON.stringify(config));
+    return;
+  }
+
+  if (command === 'request') {
+    if (args.length < 3) {
+      fatal('request requires <METHOD> <path>');
+    }
+
+    const method = args[1].toUpperCase();
+    const path = args[2];
+
+    let body: string | undefined;
+    let apiBase: string | undefined;
+
+    for (let i = 3; i < args.length; i++) {
+      if (args[i] === '--body' && i + 1 < args.length) {
+        body = args[++i];
+      } else if (args[i] === '--api-base' && i + 1 < args.length) {
+        apiBase = args[++i];
+      }
+    }
+
+    const client = createSkillClient(apiBase ? { apiBase } : undefined);
+
+    const validMethods = ['GET', 'POST', 'PUT', 'PATCH', 'DELETE', 'HEAD'] as const;
+    if (!validMethods.includes(method as any)) {
+      fatal(`Invalid method: ${method}`);
+    }
+
+    const parsedBody = body ? JSON.parse(body) : undefined;
+
+    let result;
+    switch (method) {
+      case 'GET':    result = await client.get(path); break;
+      case 'POST':   result = await client.post(path, parsedBody); break;
+      case 'PUT':    result = await client.put(path, parsedBody); break;
+      case 'PATCH':  result = await client.patch(path, parsedBody); break;
+      case 'DELETE': result = await client.delete(path, parsedBody); break;
+      default:       fatal(`Unsupported method: ${method}`);
+    }
+
+    console.log(JSON.stringify(result));
+    return;
+  }
+
+  fatal(`Unknown command: ${command}`);
+}
+
+main().catch((err) => {
+  console.error(String(err?.message || err));
+  process.exit(1);
+});