feat: batch eligibility, batch claim, and batch check+claim from AI chat

- Add batch_eligibility, batch_claim, and batch_check_and_claim intents
  to AI classifier so multiple patients can be processed one by one
- Add queue processing on insurance-status and claims pages to auto-start
  the next patient after each check/claim completes
- Make patient schema firstName, lastName, phone optional so patients can
  be created with just member ID + DOB from eligibility checks
- Cancel buttons now preserve chat history instead of clearing it
- Patient-found card shows Check Eligibility, Eligibility & Appointment
  Today, and Cancel buttons
- Claim service date asks user to pick between latest appointment and
  today when they differ
- Login page subtitle styled with animated gradient

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

apps/Frontend/src/index.css

@@ -110,3 +110,13 @@
   min-width: 6rem;        /* Prevent shrinking */
   appearance: none;       /* Removes native styling */
 }
+
+@keyframes gradient-flash {
+  0%   { background-position: 100% 50%; }
+  50%  { background-position: 0% 50%; }
+  100% { background-position: 100% 50%; }
+}
+
+.animate-gradient-flash {
+  animation: gradient-flash 6s ease-in-out infinite;
+}