feat(cli): implement config display command

src/cli/config-cmd.test.ts

@@ -0,0 +1,19 @@
+import { describe, it, expect } from 'vitest';
+import { formatConfig } from './config-cmd.js';
+
+describe('config command', () => {
+  it('formats config as indented JSON with redacted secrets', () => {
+    const config = {
+      telegram: { bot_token: 'secret-123', allowed_chat_ids: [123] },
+      models: { default: { provider: 'anthropic', model: 'claude', api_key: 'sk-abc' } },
+      server: { port: 18800 },
+    };
+
+    const output = formatConfig(config);
+    expect(output).toContain('"bot_token": "***"');
+    expect(output).toContain('"api_key": "***"');
+    expect(output).toContain('"port": 18800');
+    expect(output).not.toContain('secret-123');
+    expect(output).not.toContain('sk-abc');
+  });
+});