Fix 404 on /domains/{domain_id} by adding plural route alias and updating template link

Agent-Logs-Url: https://github.com/christianlouis/dmarq/sessions/c498fef5-0a5e-4182-b765-fc3ec074b515

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

backend/app/main.py

@@ -327,6 +327,12 @@ async def domain_details(request: Request, domain_id: str):
     )
 
 
+@app.get("/domains/{domain_id}", response_class=HTMLResponse)
+async def domain_details_plural(request: Request, domain_id: str):
+    """View detailed reports for a specific domain (plural /domains/ path alias)"""
+    return await domain_details(request, domain_id)
+
+
 @app.get("/reports", response_class=HTMLResponse)
 async def reports(request: Request):
     return templates.TemplateResponse(request, "reports.html")