Add AI agent capabilities and integrate with Anthropic and LNbits

Integrate Anthropic AI for agent capabilities, introduce database schemas for jobs and invoices, and set up LNbits for payment processing.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 418bf6f8-212b-4bb0-a7a5-8231a061da4e
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: cce28acc-aeac-46ff-80ec-af4ade39e30f
Replit-Helium-Checkpoint-Created: true

artifacts/api-server/src/lib/pricing.ts

@@ -0,0 +1,8 @@
+export const EVAL_FEE_SATS = 10;
+
+export function computeWorkFeeSats(request: string): number {
+  const len = request.trim().length;
+  if (len <= 100) return 50;
+  if (len <= 300) return 100;
+  return 250;
+}