feat(parsers+api+ui+db): 999 ACK transaction set end-to-end (SP3 P3)

backend/tests/fixtures/minimal_999.txt

@@ -0,0 +1,10 @@
+ISA*00*          *00*          *ZZ*SUBMITTERID    *ZZ*RECEIVERID     *240101*1200*^*00501*000000001*0*P*:~
+GS*HC*SUBMITTERID*RECEIVERID*20240101*1200*1*X*005010X222A1~
+ST*999*0001*005010X231A1~
+AK1*HC*0001~
+AK2*837*0001~
+AK5*A~
+AK9*A*1*1*0~
+SE*5*0001~
+GE*1*1~
+IEA*1*000000001~

backend/tests/fixtures/minimal_999_rejected.txt

@@ -0,0 +1,12 @@
+ISA*00*          *00*          *ZZ*SUBMITTERID    *ZZ*RECEIVERID     *240101*1200*^*00501*000000002*0*P*:~
+GS*HC*SUBMITTERID*RECEIVERID*20240101*1200*1*X*005010X222A1~
+ST*999*0002*005010X231A1~
+AK1*HC*0001~
+AK2*837*0001~
+AK3*CLM*12*2300~
+AK4*4***8~
+AK5*R~
+AK9*R*1*0*1~
+SE*7*0002~
+GE*1*1~
+IEA*1*000000002~