feat(db): migration 007 — conversations.space_id + seed companion agent

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/db/migration_007.test.js

@@ -0,0 +1,23 @@
+import { describe, it, expect, beforeAll } from 'vitest';
+import { pool } from '../../lib/db/pool.js';
+import { resetDb } from '../helpers/db.js';
+import { migrateUp } from '../../lib/db/migrate.js';
+
+beforeAll(async () => { await resetDb(); await migrateUp(); });
+
+describe('migration 007', () => {
+  it('adds conversations.space_id column', async () => {
+    const { rows } = await pool.query(
+      `SELECT column_name FROM information_schema.columns
+       WHERE table_name='conversations' AND column_name='space_id'`
+    );
+    expect(rows).toHaveLength(1);
+  });
+
+  it('seeds a default companion agent', async () => {
+    const { rows } = await pool.query(`SELECT slug, kind, capabilities FROM agents WHERE slug='companion'`);
+    expect(rows).toHaveLength(1);
+    expect(rows[0].kind).toBe('claude');
+    expect(rows[0].capabilities).toMatchObject({ read: true, suggest: true, write: false });
+  });
+});