Add shared types package

Shared TypeScript types, Zod validators, API contract definitions,
and constants used by both server and UI. Covers agents, goals,
issues, projects, and activity entities.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/shared/src/validators/issue.ts

@@ -0,0 +1,18 @@
+import { z } from "zod";
+import { ISSUE_PRIORITIES, ISSUE_STATUSES } from "../constants.js";
+
+export const createIssueSchema = z.object({
+  title: z.string().min(1),
+  description: z.string().optional().nullable(),
+  status: z.enum(ISSUE_STATUSES).optional().default("backlog"),
+  priority: z.enum(ISSUE_PRIORITIES).optional().default("medium"),
+  projectId: z.string().uuid().optional().nullable(),
+  assigneeId: z.string().uuid().optional().nullable(),
+  goalId: z.string().uuid().optional().nullable(),
+});
+
+export type CreateIssue = z.infer<typeof createIssueSchema>;
+
+export const updateIssueSchema = createIssueSchema.partial();
+
+export type UpdateIssue = z.infer<typeof updateIssueSchema>;