Merge PR #140: refactor split ports (npmSteven) with polish fixes

Adds split-port runtime support: API and dashboard can run on separate ports.
- PORT remains canonical/base
- API_PORT optionally overrides API listener
- DASHBOARD_PORT optionally overrides dashboard listener
- API bridge server proxies OpenAI-compatible routes with 30s timeout
- Centralized port resolution in src/lib/runtime/ports.ts
- Unit tests for runtime port resolution (14 tests)
- Healthcheck extracted into scripts/healthcheck.mjs

src/shared/services/cloudSyncScheduler.ts

@@ -1,11 +1,14 @@
 import { getConsistentMachineId } from "@/shared/utils/machineId";
 import { isCloudEnabled } from "@/lib/localDb";
+import { getRuntimePorts } from "@/lib/runtime/ports";
+
+const { dashboardPort } = getRuntimePorts();
 
 const INTERNAL_BASE_URL =
   process.env.BASE_URL ||
   process.env.NEXT_PUBLIC_BASE_URL ||
   process.env.NEXT_PUBLIC_APP_URL ||
-  "http://localhost:20128";
+  `http://localhost:${dashboardPort}`;
 
 /**
  * Cloud sync scheduler