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/index.ts

@@ -0,0 +1,41 @@
+export {
+  AGENT_STATUSES,
+  AGENT_ROLES,
+  ISSUE_STATUSES,
+  ISSUE_PRIORITIES,
+  GOAL_LEVELS,
+  type AgentStatus,
+  type AgentRole,
+  type IssueStatus,
+  type IssuePriority,
+  type GoalLevel,
+} from "./constants.js";
+
+export type {
+  Agent,
+  Project,
+  Issue,
+  Goal,
+  ActivityEvent,
+} from "./types/index.js";
+
+export {
+  createAgentSchema,
+  updateAgentSchema,
+  type CreateAgent,
+  type UpdateAgent,
+  createProjectSchema,
+  updateProjectSchema,
+  type CreateProject,
+  type UpdateProject,
+  createIssueSchema,
+  updateIssueSchema,
+  type CreateIssue,
+  type UpdateIssue,
+  createGoalSchema,
+  updateGoalSchema,
+  type CreateGoal,
+  type UpdateGoal,
+} from "./validators/index.js";
+
+export { API_PREFIX, API } from "./api.js";