Add department budget % allocation

- Budgets page: new dept split section with % inputs, equal-split button, save
- Weekly/Monthly: per-dept budget column using dept pcts from actuals response
- Backend: dept_budget_pcts in ALLOWED_KEYS; actuals returns dept_pcts map;
  budgets route adds GET /dept-config + PUT /dept-pcts endpoints

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

frontend/src/api.ts

@@ -1,4 +1,4 @@
-import type { DeptActuals, DeptScheduled, NetSalesDay, WageBudget, AppSetting } from './types'
+import type { DeptActuals, DeptScheduled, NetSalesDay, WageBudget, AppSetting, DeptPct } from './types'
 
 const BASE = '/wages/api'
 
@@ -20,7 +20,7 @@ async function request<T>(path: string, opts: RequestInit = {}): Promise<T> {
   return res.json()
 }
 
-export function getActuals(from: string, to: string): Promise<{ departments: DeptActuals[]; show_oncosts: boolean }> {
+export function getActuals(from: string, to: string): Promise<{ departments: DeptActuals[]; show_oncosts: boolean; dept_pcts: Record<string, number> }> {
   return request(`/actuals?from=${from}&to=${to}`)
 }
 
@@ -67,6 +67,14 @@ export function saveSettings(settings: { key: string; value: string }[]): Promis
   return request('/settings', { method: 'PUT', body: JSON.stringify({ settings }) })
 }
 
+export function getDeptConfig(): Promise<{ depts: DeptPct[] }> {
+  return request('/budgets/dept-config')
+}
+
+export function saveDeptPcts(pcts: { id: string; pct: number }[]): Promise<{ ok: boolean }> {
+  return request('/budgets/dept-pcts', { method: 'PUT', body: JSON.stringify({ pcts }) })
+}
+
 export function downloadExport(view: string, from: string, to: string): void {
   window.open(`${BASE}/export?view=${view}&from=${from}&to=${to}`, '_blank')
 }