fix: allow claims without appointment + support post/core multi-tooth input

- Make appointmentId nullable/optional in Prisma Zod schema via @zod rich
  comment so claims can be submitted without an existing appointment
- Convert undefined appointmentId to null in all claim form handlers and
  the backend claim creation endpoint
- Add AI classifier rule for expanding one procedure across multiple
  comma-separated tooth numbers (e.g. "post/core on #23, 24, 25, 26")
- Add "post/core" (slash) alias to CDT lookup maps

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

packages/db/generated/prisma/index.d.ts

@@ -14580,6 +14580,9 @@ export namespace Prisma {
     scalars: $Extensions.GetPayloadResult<{
       id: number
       patientId: number
+      /**
+       * @zod.number.int().nullable().optional()
+       */
       appointmentId: number | null
       userId: number
       staffId: number