fix: default tooth # for 2PA and skip PDF popup for AI chat claims

- 2PA with no explicit tooth numbers now defaults to D0220 #8 / D0230 #24
- Claims submitted via the AI chat column no longer auto-open the PDF preview modal

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/Backend/src/ai/cdt-lookup.ts

@@ -317,10 +317,15 @@ function parseMultiPaCode(input: string): CdtMatch[] | null {
 
   // Extract all tooth numbers from the full input string
   const toothMatches = [...input.matchAll(/#\s*(\d{1,2})\b/g)];
-  const teeth: string[] = toothMatches
+  let teeth: string[] = toothMatches
     .map((tm) => tm[1]!)
     .filter((t) => { const n = parseInt(t, 10); return n >= 1 && n <= 32; });
 
+  // "2PA" with no tooth numbers given defaults to #8 (D0220) and #24 (D0230)
+  if (count === 2 && teeth.length === 0) {
+    teeth = ["8", "24"];
+  }
+
   const d0220 = ALL_CODES.find((r) => r["Procedure Code"] === "D0220");
   const d0230 = ALL_CODES.find((r) => r["Procedure Code"] === "D0230");