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.

backend/app/services/auth.py

@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from typing import Dict, Optional
+
+from backend.app.core.security import (
+    create_access_token,
+    get_password_hash,
+    verify_password,
+)
+from backend.app.models import AuthResponse, UserInDB, UserPublic
+
+_DEMO_USER = UserInDB(
+    username="demo",
+    full_name="Demo Engineer",
+    hashed_password=get_password_hash("railgame123"),
+)
+
+_FAKE_USERS: Dict[str, UserInDB] = {_DEMO_USER.username: _DEMO_USER}
+
+
+def get_user(username: str) -> Optional[UserInDB]:
+    return _FAKE_USERS.get(username)
+
+
+def authenticate_user(username: str, password: str) -> Optional[UserInDB]:
+    user = get_user(username)
+    if not user:
+        return None
+    if not verify_password(password, user.hashed_password):
+        return None
+    return user
+
+
+def issue_token_for_user(user: UserInDB) -> AuthResponse:
+    return AuthResponse(
+        access_token=create_access_token(subject=user.username),
+        token_type="bearer",
+        user=to_public_user(user),
+    )
+
+
+def to_public_user(user: UserInDB) -> UserPublic:
+    return UserPublic(username=user.username, full_name=user.full_name)
+
+
+def register_user(username: str, password: str, full_name: Optional[str] = None) -> UserInDB:
+    normalized_username = username.strip()
+    if not normalized_username:
+        raise ValueError("Username must not be empty")
+    if normalized_username in _FAKE_USERS:
+        raise ValueError("Username already exists")
+
+    user = UserInDB(
+        username=normalized_username,
+        full_name=full_name.strip() if full_name else None,
+        hashed_password=get_password_hash(password),
+    )
+    _FAKE_USERS[normalized_username] = user
+    return user