feat: Refactor template handling, improve scheduler functions, and add timezone utilities

- Moved Jinja2 template setup to a shared configuration file (templates_config.py) for consistent usage across routers.
- Introduced timezone utilities in a new module (timezone.py) to handle UTC to local time conversions and formatting.
- Updated all relevant routers to use the new shared template configuration and timezone filters.
- Enhanced templates to utilize local time formatting for various datetime fields, improving user experience with timezone awareness.

backend/routers/slm_ui.py

@@ -6,7 +6,6 @@ Provides endpoints for SLM dashboard cards, detail pages, and real-time data.
 
 from fastapi import APIRouter, Depends, HTTPException, Request
 from fastapi.responses import HTMLResponse
-from fastapi.templating import Jinja2Templates
 from sqlalchemy.orm import Session
 from datetime import datetime
 import httpx
@@ -15,11 +14,11 @@ import os
 
 from backend.database import get_db
 from backend.models import RosterUnit
+from backend.templates_config import templates
 
 logger = logging.getLogger(__name__)
 
 router = APIRouter(prefix="/slm", tags=["slm-ui"])
-templates = Jinja2Templates(directory="templates")
 
 SLMM_BASE_URL = os.getenv("SLMM_BASE_URL", "http://172.19.0.1:8100")