feat: Initialize frontend and backend structure with essential configurations

- Added TypeScript build info for frontend.
- Created Vite configuration for React application.
- Implemented pre-commit hook to run checks before commits.
- Set up PostgreSQL Dockerfile with PostGIS support and initialization scripts.
- Added database creation script for PostgreSQL with necessary extensions.
- Established Python project configuration with dependencies and development tools.
- Developed pre-commit script to enforce code quality checks for backend and frontend.
- Created PowerShell script to set up Git hooks path.

frontend/src/services/api.ts

@@ -0,0 +1,84 @@
+import type { AuthResponse, LoginPayload, RegisterPayload } from '../types/auth';
+import type { Station, Track, Train } from '../types/domain';
+
+export class ApiError extends Error {
+  readonly status: number;
+
+  constructor(message: string, status: number) {
+    super(message);
+    this.name = 'ApiError';
+    this.status = status;
+  }
+}
+
+export interface NetworkSnapshot {
+  readonly stations: Station[];
+  readonly tracks: Track[];
+  readonly trains: Train[];
+}
+
+const JSON_HEADERS = {
+  accept: 'application/json',
+  'content-type': 'application/json',
+};
+
+export async function login(credentials: LoginPayload): Promise<AuthResponse> {
+  const response = await fetch('/api/auth/login', {
+    method: 'POST',
+    headers: JSON_HEADERS,
+    body: JSON.stringify(credentials),
+  });
+
+  if (!response.ok) {
+    throw new ApiError('Invalid username or password', response.status);
+  }
+
+  return (await response.json()) as AuthResponse;
+}
+
+export async function register(credentials: RegisterPayload): Promise<AuthResponse> {
+  const response = await fetch('/api/auth/register', {
+    method: 'POST',
+    headers: JSON_HEADERS,
+    body: JSON.stringify(credentials),
+  });
+
+  if (!response.ok) {
+    const message =
+      response.status === 409
+        ? 'Username already exists'
+        : 'Registration failed. Please try again.';
+    throw new ApiError(message, response.status);
+  }
+
+  return (await response.json()) as AuthResponse;
+}
+
+export async function fetchNetworkSnapshot(
+  token: string,
+  signal?: AbortSignal
+): Promise<NetworkSnapshot> {
+  const response = await fetch('/api/network', {
+    method: 'GET',
+    headers: {
+      accept: 'application/json',
+      Authorization: `Bearer ${token}`,
+    },
+    signal,
+  });
+
+  if (!response.ok) {
+    const message =
+      response.status === 401
+        ? 'Authorization required. Please sign in again.'
+        : `Failed to fetch network snapshot (status ${response.status})`;
+    throw new ApiError(message, response.status);
+  }
+
+  const data = (await response.json()) as NetworkSnapshot;
+  return {
+    stations: data.stations ?? [],
+    tracks: data.tracks ?? [],
+    trains: data.trains ?? [],
+  };
+}