feat: AI chat Eligibility & Appointment button with 15-min slots and Column B fallback

- Add "Eligibility & Appointment" button to chatbot eligibility-id-ready card
- For known patients: creates today's appointment immediately, then opens eligibility page
- For unknown patients: navigates to eligibility page; after Selenium creates the patient,
  auto-creates appointment via tryAppointmentFromChatbot on the insurance-status page
- Update MH Eligibility & Appointment button to create a today's schedule slot instead of
  navigating to the appointments page; shows PDF preview on completion
- createAppointmentToday falls back from Column A to Column B when Column A is full;
  returns column label in response so UI can display it
- Set AI-scheduled appointment duration to 15 minutes

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/Backend/src/routes/ai-settings.ts

@@ -1,7 +1,7 @@
 import express, { Request, Response } from "express";
 import { storage } from "../storage";
 import { classifyInternalChat } from "../ai/internal-chat-graph";
-import { runInternalChatWorkflow } from "../ai/internal-chat-workflow";
+import { runInternalChatWorkflow, createAppointmentToday } from "../ai/internal-chat-workflow";
 import { resolveAiProvider } from "../ai/llm-factory";
 
 const router = express.Router();
@@ -309,4 +309,18 @@ router.post("/internal-chat", async (req: Request, res: Response): Promise<any>
   }
 });
 
+router.post("/create-appointment-today", async (req: Request, res: Response): Promise<any> => {
+  try {
+    const userId = req.user?.id;
+    if (!userId) return res.status(401).json({ message: "Unauthorized" });
+    const { patientId } = req.body;
+    if (!patientId) return res.status(400).json({ message: "patientId is required" });
+    const result = await createAppointmentToday(Number(patientId), userId, storage);
+    if ("error" in result) return res.status(409).json({ message: result.error });
+    return res.status(200).json(result);
+  } catch (err) {
+    return res.status(500).json({ error: "Failed to create appointment", details: String(err) });
+  }
+});
+
 export default router;