feat: add Procedure Duration/Time Slot settings and custom appointment type

- Add Settings > Advanced > Procedure Duration/Time Slot page with three sections:
  1. Procedure Duration: CDT codes with durations (editable table, save per section)
  2. Doctor Time Slot: drag-to-block visual grid (A/B/C columns, 8 AM–9 PM, edit/delete slots)
  3. Hygienist Time Slot: procedure descriptions with durations
- Backend: ProcedureTimeslot Prisma model, storage, and GET/PUT /api/procedure-timeslot route
- DB migration: procedure_timeslot table
- Appointment form: when type is "Other", show a free-text input for custom description; saved as other:<description> and decoded for display on the schedule card

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

apps/Frontend/src/components/layout/sidebar.tsx

@@ -28,6 +28,7 @@ import {
   Bot,
   Clock,
   Building2,
+  Timer,
 } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { useMemo, useState, useEffect } from "react";
@@ -233,6 +234,11 @@ export function Sidebar() {
             path: "/settings/ai",
             icon: <Bot className="h-4 w-4 text-gray-400" />,
           },
+          {
+            name: "Procedure Duration/Time Slot",
+            path: "/settings/proceduretimeslot",
+            icon: <Timer className="h-4 w-4 text-gray-400" />,
+          },
         ],
       },
     ],