feat: Set up SessionMiddleware and Jinja2 Template Configuration

- Add SECRET_KEY environment variable and .env file for session management
- Configure SessionMiddleware with FastAPI for user session handling
- Set up Jinja2 template engine with template directory configuration
- Mount static files directory for CSS, JS, and image assets
- Create comprehensive base.html template with Bootstrap 5 CDN
- Add Bootstrap Icons and custom styling support
- Include responsive navigation with user authentication state
- Create placeholder CSS and JavaScript files for customization
- Add aiofiles dependency for static file serving

This establishes the web framework foundation with session management
and templating system ready for frontend development.

app/main.py

@@ -5,20 +5,36 @@ This module initializes the FastAPI application, sets up database connections,
 and provides the main application instance.
 """
 
+import os
 import logging
 from contextlib import asynccontextmanager
 
-from fastapi import FastAPI, Depends
+from fastapi import FastAPI, Depends, Request
+from fastapi.middleware.sessions import SessionMiddleware
+from fastapi.middleware.cors import CORSMiddleware
+from fastapi.staticfiles import StaticFiles
+from fastapi.templating import Jinja2Templates
 from sqlalchemy.orm import Session
+from dotenv import load_dotenv
 
 from .database import create_tables, get_db, get_database_url
 from .models import User
 
+# Load environment variables
+load_dotenv()
+
+# Get SECRET_KEY from environment variables
+SECRET_KEY = os.getenv("SECRET_KEY")
+if not SECRET_KEY:
+    raise ValueError("SECRET_KEY environment variable must be set")
 
 # Configure logging
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
+# Configure Jinja2 templates
+templates = Jinja2Templates(directory="app/templates")
+
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
@@ -54,6 +70,21 @@ app = FastAPI(
     lifespan=lifespan
 )
 
+# Add CORS middleware for cross-origin requests
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],  # In production, specify allowed origins
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+# Add SessionMiddleware for session management
+app.add_middleware(SessionMiddleware, secret_key=SECRET_KEY)
+
+# Mount static files directory
+app.mount("/static", StaticFiles(directory="static"), name="static")
+
 
 @app.get("/")
 async def root():