Add Bitcoin/LND/LNbits local node setup scripts and node diagnostics endpoint

- scripts/bitcoin-ln-node/setup.sh: one-shot installer for Bitcoin Core (pruned mainnet), LND, and LNbits on Apple Silicon Mac. Generates secrets, writes configs, installs launchd plists for auto-start.
- scripts/bitcoin-ln-node/start.sh: start all services via launchctl; waits for RPC readiness and auto-unlocks LND wallet.
- scripts/bitcoin-ln-node/stop.sh: graceful shutdown (lncli stop → bitcoin-cli stop).
- scripts/bitcoin-ln-node/status.sh: full health check (Bitcoin sync %, LND channels/balance, LNbits HTTP, bore tunnel). Supports --json mode for machine consumption.
- scripts/bitcoin-ln-node/expose.sh: opens bore tunnel from LNbits port 5000 to bore.pub for Replit access.
- scripts/bitcoin-ln-node/get-lnbits-key.sh: fetches LNbits admin API key and prints Replit secret values.
- artifacts/api-server/src/routes/node-diagnostics.ts: GET /api/admin/node-status (JSON) and /api/admin/node-status/html — Timmy self-diagnoses its LNbits/LND connectivity and reports issues.

artifacts/api-server/src/routes/index.ts

@@ -7,6 +7,7 @@ import demoRouter from "./demo.js";
 import devRouter from "./dev.js";
 import testkitRouter from "./testkit.js";
 import uiRouter from "./ui.js";
+import nodeDiagnosticsRouter from "./node-diagnostics.js";
 
 const router: IRouter = Router();
 
@@ -17,6 +18,7 @@ router.use(sessionsRouter);
 router.use(demoRouter);
 router.use(testkitRouter);
 router.use(uiRouter);
+router.use(nodeDiagnosticsRouter);
 
 if (process.env.NODE_ENV !== "production") {
   router.use(devRouter);