fix: extend security sanitization + add 10 tests for merged community PRs

- Extend json_safe() to ERROR_CLASS and FAILED_STEP fields
- Improve ERROR_MESSAGE escaping to handle backslashes and newlines
- Replace python3 with bun for JSON validation in gstack-review-log
- Add 7 telemetry injection prevention tests
- Add 2 review-log JSON validation tests
- Add 1 discover-skills hidden directory filtering test

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

test/review-log.test.ts

@@ -0,0 +1,77 @@
+import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
+import { execSync, ExecSyncOptionsWithStringEncoding } from 'child_process';
+import * as fs from 'fs';
+import * as path from 'path';
+import * as os from 'os';
+
+const ROOT = path.resolve(import.meta.dir, '..');
+const BIN = path.join(ROOT, 'bin');
+
+let tmpDir: string;
+let slugDir: string;
+
+function run(input: string, opts: { expectFail?: boolean } = {}): { stdout: string; exitCode: number } {
+  const execOpts: ExecSyncOptionsWithStringEncoding = {
+    cwd: ROOT,
+    env: { ...process.env, GSTACK_HOME: tmpDir },
+    encoding: 'utf-8',
+    timeout: 10000,
+  };
+  try {
+    const stdout = execSync(`${BIN}/gstack-review-log '${input.replace(/'/g, "'\\''")}'`, execOpts).trim();
+    return { stdout, exitCode: 0 };
+  } catch (e: any) {
+    if (opts.expectFail) {
+      return { stdout: e.stderr?.toString() || '', exitCode: e.status || 1 };
+    }
+    throw e;
+  }
+}
+
+beforeEach(() => {
+  tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'gstack-revlog-'));
+  // gstack-review-log uses gstack-slug which needs a git repo — create the projects dir
+  // with a predictable slug by pre-creating the directory structure
+  slugDir = path.join(tmpDir, 'projects');
+  fs.mkdirSync(slugDir, { recursive: true });
+});
+
+afterEach(() => {
+  fs.rmSync(tmpDir, { recursive: true, force: true });
+});
+
+describe('gstack-review-log', () => {
+  test('appends valid JSON to review JSONL file', () => {
+    const input = '{"skill":"plan-eng-review","status":"clean"}';
+    const result = run(input);
+    expect(result.exitCode).toBe(0);
+
+    // Find the JSONL file that was written
+    const projectDirs = fs.readdirSync(slugDir);
+    expect(projectDirs.length).toBeGreaterThan(0);
+    const projectDir = path.join(slugDir, projectDirs[0]);
+    const jsonlFiles = fs.readdirSync(projectDir).filter(f => f.endsWith('.jsonl'));
+    expect(jsonlFiles.length).toBeGreaterThan(0);
+
+    const content = fs.readFileSync(path.join(projectDir, jsonlFiles[0]), 'utf-8').trim();
+    const parsed = JSON.parse(content);
+    expect(parsed.skill).toBe('plan-eng-review');
+    expect(parsed.status).toBe('clean');
+  });
+
+  test('rejects non-JSON input with non-zero exit code', () => {
+    const result = run('not json at all', { expectFail: true });
+    expect(result.exitCode).not.toBe(0);
+
+    // Verify nothing was written
+    const projectDirs = fs.readdirSync(slugDir);
+    if (projectDirs.length > 0) {
+      const projectDir = path.join(slugDir, projectDirs[0]);
+      const jsonlFiles = fs.readdirSync(projectDir).filter(f => f.endsWith('.jsonl'));
+      if (jsonlFiles.length > 0) {
+        const content = fs.readFileSync(path.join(projectDir, jsonlFiles[0]), 'utf-8').trim();
+        expect(content).toBe('');
+      }
+    }
+  });
+});