fix: resolve Zod v4 record type error and worker TypeScript compilation

- packages/shared/src/schemas/agent.ts: z.record(z.unknown()) → z.record(z.string(), z.unknown())
- Dockerfile.worker: add TypeScript compilation support (tsx)

Fixes #build-web and #build-worker container failures.

packages/shared/src/schemas/agent.ts

@@ -19,7 +19,7 @@ export const agentActivitySchema = z.object({
   action: z.string(),
   entity_type: z.string().optional(),
   entity_id: z.string().optional(),
-  details: z.record(z.unknown()).optional(),
+  details: z.record(z.string(), z.unknown()).optional(),
   success: z.boolean().default(true),
   error_message: z.string().optional(),
   created: z.string().datetime(),