Add shared types for agent hiring, config revisions, costs breakdown, and sidebar badges

Add AgentConfigRevision, CostByAgent, SidebarBadges types. Add createAgentHireSchema
with source issue linking and linkIssueApprovalSchema. Extend approval validator with
issueIds. Update cost summary to generic period naming. Add sidebar badges API path.

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

packages/shared/src/api.ts

@@ -11,4 +11,5 @@ export const API = {
   costs: `${API_PREFIX}/costs`,
   activity: `${API_PREFIX}/activity`,
   dashboard: `${API_PREFIX}/dashboard`,
+  sidebarBadges: `${API_PREFIX}/sidebar-badges`,
 } as const;