fix: correct license key part count validation (5 not 6)

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

apps/Backend/src/routes/license.ts

@@ -11,7 +11,7 @@ const SECRET = process.env.LICENSE_SECRET || "";
 function validateKey(key: string): { valid: boolean; expiry?: string; error?: string } {
   // Format: DENTAL-{24-char-signature}-{YYYY-MM-DD}
   const parts = key.trim().split("-");
-  if (parts.length !== 6 || parts[0] !== "DENTAL") {
+  if (parts.length !== 5 || parts[0] !== "DENTAL") {
     return { valid: false, error: "Invalid license key format" };
   }