feat(expense): add frontend models + API services

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

APP/src/app/features/expense/services/expense-api.service.ts

@@ -0,0 +1,45 @@
+import { Injectable } from '@angular/core';
+import { HttpClient, HttpParams } from '@angular/common/http';
+import { Observable } from 'rxjs';
+import { ApiConfigService } from '../../../core/services/api-config.service';
+import {
+  PagedResult, ExpenseListItemDto, ExpenseDto, CreateExpenseRequest, UpdateExpenseRequest,
+  RejectExpenseRequest, PayExpenseRequest,
+} from '../models/expense.model';
+
+export interface ExpenseQuery {
+  page?: number; pageSize?: number; search?: string; ministryId?: number;
+  categoryGroupId?: number; status?: string; from?: string; to?: string;
+}
+
+@Injectable({ providedIn: 'root' })
+export class ExpenseApiService {
+  private readonly endpoint: string;
+  constructor(private http: HttpClient, apiConfig: ApiConfigService) {
+    this.endpoint = apiConfig.getApiUrl('expenses');
+  }
+  private toParams(q: Record<string, unknown>): HttpParams {
+    let p = new HttpParams();
+    for (const [k, v] of Object.entries(q)) if (v !== undefined && v !== null && v !== '') p = p.set(k, String(v));
+    return p;
+  }
+  getPaged(q: ExpenseQuery): Observable<PagedResult<ExpenseListItemDto>> {
+    return this.http.get<PagedResult<ExpenseListItemDto>>(this.endpoint, { params: this.toParams(q as Record<string, unknown>) });
+  }
+  getMine(status?: string, page = 1, pageSize = 50): Observable<PagedResult<ExpenseListItemDto>> {
+    return this.http.get<PagedResult<ExpenseListItemDto>>(`${this.endpoint}/mine`, { params: this.toParams({ status, page, pageSize }) });
+  }
+  getById(id: number): Observable<ExpenseDto> { return this.http.get<ExpenseDto>(`${this.endpoint}/${id}`); }
+  create(r: CreateExpenseRequest): Observable<{ id: number }> { return this.http.post<{ id: number }>(this.endpoint, r); }
+  update(id: number, r: UpdateExpenseRequest): Observable<void> { return this.http.put<void>(`${this.endpoint}/${id}`, r); }
+  delete(id: number): Observable<void> { return this.http.delete<void>(`${this.endpoint}/${id}`); }
+  submit(id: number): Observable<void> { return this.http.post<void>(`${this.endpoint}/${id}/submit`, {}); }
+  approve(id: number): Observable<void> { return this.http.post<void>(`${this.endpoint}/${id}/approve`, {}); }
+  reject(id: number, r: RejectExpenseRequest): Observable<void> { return this.http.post<void>(`${this.endpoint}/${id}/reject`, r); }
+  pay(id: number, r: PayExpenseRequest): Observable<void> { return this.http.post<void>(`${this.endpoint}/${id}/pay`, r); }
+  uploadReceipt(id: number, file: File): Observable<void> {
+    const form = new FormData(); form.append('file', file);
+    return this.http.post<void>(`${this.endpoint}/${id}/receipt`, form);
+  }
+  receiptUrl(id: number): string { return `${this.endpoint}/${id}/receipt`; }
+}