Phase 1: Fix TypeScript compilation — add missing API functions and fix hook signatures

- Add 8 missing API client functions (getBreakPeriods, createBreakPeriod, deleteBreakPeriod, getTips, getParentalLeave, getPlannedDays, createPlannedDay, deletePlannedDay)
- Fix useAnalytics to accept optional childId parameter
- Fix ApiError strict optional properties handling
- Export HeaderProps from Header component
- Update hook tests to use correct data structures and optional parameters

npx tsc --noEmit now passes with zero errors.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

frontend/src/services/api.ts

@@ -19,7 +19,7 @@ import type {
   WorkspaceCreateRequest,
   WorkspaceOverview,
 } from '@/types'
-import type { Workspace } from '@/types'
+import type { Workspace, BreakPeriod, Tip, PlannedLeaveDay } from '@/types'
 
 const BASE = '/api'
 
@@ -42,13 +42,15 @@ async function apiFetch<T>(
   }
   const response = await fetch(`${BASE}${path}`, { ...options, headers })
   if (!response.ok) {
-    let error = { code: String(response.status), message: response.statusText, details: undefined }
+    let error: { code: string; message: string; details?: Record<string, unknown> } = {
+      code: String(response.status),
+      message: response.statusText,
+    }
     try {
       const body = (await response.json()) as { detail?: string; code?: string; message?: string }
       error = {
         code: body.code ?? String(response.status),
         message: body.detail ?? body.message ?? response.statusText,
-        details: undefined,
       }
     } catch {
       // response body wasn't JSON — use status text
@@ -157,3 +159,68 @@ export async function getWorkspaceOverview(
 ): Promise<WorkspaceOverview> {
   return apiFetch(`/analytics/${workspaceId}/overview?child_id=${childId}`)
 }
+
+// ---------------------------------------------------------------------------
+// Break Periods
+// ---------------------------------------------------------------------------
+
+export async function getBreakPeriods(workspaceId: string): Promise<BreakPeriod[]> {
+  return apiFetch(`/workspaces/${workspaceId}/break-periods`)
+}
+
+export async function createBreakPeriod(
+  workspaceId: string,
+  payload: { startDate: string; endDate: string; name: string; targetWeeks: number },
+): Promise<BreakPeriod> {
+  return apiFetch(`/workspaces/${workspaceId}/break-periods`, {
+    method: 'POST',
+    body: JSON.stringify(payload),
+  })
+}
+
+export async function deleteBreakPeriod(id: string): Promise<void> {
+  return apiFetch(`/break-periods/${id}`, { method: 'DELETE' })
+}
+
+// ---------------------------------------------------------------------------
+// Tips
+// ---------------------------------------------------------------------------
+
+export async function getTips(workspaceId: string): Promise<Tip[]> {
+  return apiFetch(`/workspaces/${workspaceId}/tips`)
+}
+
+// ---------------------------------------------------------------------------
+// Parental Leave Fetch
+// ---------------------------------------------------------------------------
+
+export async function getParentalLeave(workspaceId: string): Promise<ParentalLeaveFetch> {
+  return apiFetch(`/workspaces/${workspaceId}/parental-leave`)
+}
+
+// ---------------------------------------------------------------------------
+// Planned Days
+// ---------------------------------------------------------------------------
+
+export async function getPlannedDays(
+  workspaceId: string,
+  childId?: string,
+): Promise<PlannedLeaveDay[]> {
+  const query = childId ? `?childId=${childId}` : ''
+  return apiFetch(`/workspaces/${workspaceId}/planned-days${query}`)
+}
+
+export async function createPlannedDay(
+  workspaceId: string,
+  childId: string,
+  payload: { date: string; leaveType: string },
+): Promise<PlannedLeaveDay> {
+  return apiFetch(`/workspaces/${workspaceId}/planned-days`, {
+    method: 'POST',
+    body: JSON.stringify({ ...payload, childId }),
+  })
+}
+
+export async function deletePlannedDay(id: string): Promise<void> {
+  return apiFetch(`/planned-days/${id}`, { method: 'DELETE' })
+}