feat: AI chatbot preauth intent, UnitedDH pre-auth improvements

- Add preauth intent to AI chatbot (classifier, workflow, frontend UI card)
- Auto-prefill preauth form with CDT codes, service date, and mapped prices
- Auto-trigger preauth Selenium handler by insurance siteKey (MH/Tufts/CCA/UnitedDH)
- Default tentative service date to today+3 for preauth (user didn't pick a date)
- Fix #number always means tooth number, distributes to all procedures in comma list
- Fix bare "post"/"pos" → D2954 (was matching D2955 via keyword scorer)
- UnitedDH pre-auth: fill procedure date with Ctrl+A to overwrite prefilled value
- UnitedDH pre-auth: select Location "Summit Dental Care" in step1 (same as billing entity)
- UnitedDH pre-auth: remove page refresh in step9 to preserve pre-auth number
- UnitedDH pre-auth: wait for table rows before extracting pre-auth number
- UnitedDH pre-auth/claim: explicit wait for Submit button after file upload (no sleep)

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

apps/Backend/src/ai/internal-chat-graph.ts

@@ -9,6 +9,7 @@ export type InternalChatIntent =
   | "find_patient"          // look up patient record only
   | "schedule_appointment"  // add patient to today's (or specified) schedule
   | "claim_only"            // submit claim for procedures (no eligibility check)
+  | "preauth"               // submit pre-authorization for procedures
   | "navigate_claims"
   | "navigate_schedule"
   | "navigate_eligibility"
@@ -83,6 +84,11 @@ Intents:
                           e.g. "claim perio exam, 2BW for John Smith"
                           Use this when no eligibility check is requested — just billing/claiming services
                           Always extract appointmentDate when a date or "today" is mentioned
+- preauth               : submit a pre-authorization request for procedures
+                          e.g. "preauth rct, post, crown for John Smith"
+                          e.g. "pre auth #20 rct, post, crown for Zhiyuan Chen"
+                          e.g. "pre-auth D3320, D2952, D2740 for Maria"
+                          Use this when the user says "preauth", "pre auth", "pre-auth", or "prior auth"
 - navigate_claims       : open the claims page
 - navigate_schedule     : open the appointments/schedule page
 - navigate_eligibility  : open the insurance eligibility page
@@ -99,8 +105,12 @@ Rules:
   Only include actual clinical procedures in procedureNames.
 - For composite fillings with a tooth number, preserve the EXACT notation including tooth# and surfaces:
   e.g. "composite #29 O", "#8 MO", "composite #11 MOD" — keep the #number and surface letters together as one entry
+- #number always means a TOOTH number (never a case or pre-auth reference). When a single #number appears before a comma-separated list of procedures, apply it to EVERY procedure in the list.
+  e.g. "#20 rct, post, crown" → ["#20 rct", "#20 post", "#20 crown"]
+  e.g. "preauth #20 rct, pos, crown" → ["#20 rct", "#20 pos", "#20 crown"]
+  e.g. "#14 rct, buildup, crown" → ["#14 rct", "#14 buildup", "#14 crown"]
 - For RCT/root canal with a tooth number, preserve the tooth# in the entry:
-  e.g. "rct #29", "#14 root canal", "rct #6" — keep the #number with the procedure so the correct code can be selected
+  e.g. "rct #29", "#14 root canal", "rct #6", "#20 rct" — keep the #number with the procedure so the correct code can be selected
 - For SRP with a quadrant abbreviation (UL, UR, LL, LR), keep the code and quadrant together as one entry:
   e.g. "D4341 UL", "4341 LR", "D4342 UR" — the quadrant always travels with the SRP code
 - For multiple PA X-rays with tooth numbers, expand each PA into its own entry: