fix: harden startup and schema repair contracts

Reliability patch covering startup path resolution, install marker compatibility, export CLI request contracts, schema repair safety, hard-stop retry-loop handling, and the PR babysit status helper.

tests/plugin-version-check.test.ts

@@ -0,0 +1,65 @@
+import { describe, it, expect, beforeEach, afterEach } from 'bun:test';
+import { mkdirSync, writeFileSync, rmSync } from 'fs';
+import { spawnSync } from 'child_process';
+import { join } from 'path';
+import { tmpdir } from 'os';
+
+const VERSION_CHECK_SCRIPT = join(import.meta.dir, '..', 'plugin', 'scripts', 'version-check.js');
+
+function runVersionCheck(root: string) {
+  const env = { ...process.env, CLAUDE_PLUGIN_ROOT: root };
+  delete env.CLAUDE_MEM_CODEX_HOOK;
+
+  return spawnSync('node', [VERSION_CHECK_SCRIPT], {
+    encoding: 'utf-8',
+    env,
+  });
+}
+
+describe('plugin/scripts/version-check.js install marker compatibility', () => {
+  let tempDir: string;
+
+  beforeEach(() => {
+    tempDir = join(
+      tmpdir(),
+      `version-check-test-${Date.now()}-${Math.random().toString(36).slice(2)}`,
+    );
+    mkdirSync(tempDir, { recursive: true });
+    writeFileSync(join(tempDir, 'package.json'), JSON.stringify({ version: '12.4.4' }));
+  });
+
+  afterEach(() => {
+    rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('accepts a matching legacy plain-text marker without an upgrade hint', () => {
+    writeFileSync(join(tempDir, '.install-version'), '12.4.4\n');
+
+    const result = runVersionCheck(tempDir);
+
+    expect(result.status).toBe(0);
+    expect(result.stdout).toBe('');
+    expect(result.stderr).toBe('');
+  });
+
+  it('accepts a matching legacy plain-text marker with a leading v', () => {
+    writeFileSync(join(tempDir, '.install-version'), 'v12.4.4\n');
+
+    const result = runVersionCheck(tempDir);
+
+    expect(result.status).toBe(0);
+    expect(result.stdout).toBe('');
+    expect(result.stderr).toBe('');
+  });
+
+  it('emits an upgrade hint for a mismatched legacy plain-text marker', () => {
+    writeFileSync(join(tempDir, '.install-version'), '12.4.3\n');
+
+    const result = runVersionCheck(tempDir);
+
+    expect(result.status).toBe(0);
+    expect(result.stderr).toContain(
+      'claude-mem: upgraded to v12.4.4 - run: npx claude-mem@latest install',
+    );
+  });
+});