v2: SQLite state adapter, admin commands, compact feedback

- Replace in-memory Chat SDK state with SqliteStateAdapter — thread
  subscriptions now persist across restarts
- Add migration 002 for chat_sdk_kv, subscriptions, locks, lists tables
- Handle /clear in agent-runner (reset sessionId) — SDK has
  supportsNonInteractive:false for this command
- Pass /compact, /context, /cost, /files through to SDK as admin commands
- Skip admin commands in follow-up poll so they start fresh queries
- Emit compact_boundary events as user-visible feedback messages
- Pass NANOCLAW_ADMIN_USER_ID and NANOCLAW_ASSISTANT_NAME to containers

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

src/db/db-v2.test.ts

@@ -62,7 +62,7 @@ describe('migrations', () => {
     const db = initTestDb();
     runMigrations(db);
     const row = db.prepare('SELECT MAX(version) as v FROM schema_version').get() as { v: number };
-    expect(row.v).toBe(1);
+    expect(row.v).toBe(2);
   });
 });