fix(worker): break circular import by extracting PgBoss singleton

incremental-sync.ts and api/cw/sync.ts imported getBoss() from workert.ts.
When workert.ts (the entry point) dynamically imported incremental-sync.ts,
it triggered a circular module re-evaluation that hung indefinitely.

Extract the PgBoss singleton and getBoss() factory to a new boss-instance.ts
module that neither has top-level async side-effects nor imports from
workert.ts. All consumers (workert.ts, index.ts, incremental-sync.ts,
cw/sync.ts) now import from boss-instance.ts instead.

api/src/boss-instance.ts

@@ -0,0 +1,30 @@
+/**
+ * Shared PgBoss singleton — kept in its own module to break circular imports
+ * between workert.ts and the worker modules that call getBoss().
+ */
+import { PgBoss } from "pg-boss";
+
+function makePgBossUrl(rawUrl: string): string {
+  try {
+    const u = new URL(rawUrl);
+    // 30-second statement timeout to prevent individual SQL queries from
+    // hanging indefinitely if the DB server stops responding mid-query.
+    u.searchParams.set("options", "-c statement_timeout=30000");
+    return u.toString();
+  } catch {
+    return rawUrl;
+  }
+}
+
+export const boss = new PgBoss({
+  connectionString: makePgBossUrl(process.env.DATABASE_URL!),
+  connectionTimeoutMillis: 15_000,
+});
+
+boss.on("error", (err) => {
+  console.error("[worker] PgBoss error", err);
+});
+
+export function getBoss(): PgBoss {
+  return boss;
+}