test: GTDT e2e, v2 write-path guards, and PG test env support

Add JacksonXmlCodec/GtdtHandler/Pipeline tests, PgTestSupport for MSGX_PG_*,
and update smoke/poller expectations for real decode semantics.

src/test/kotlin/com/gzzn/omms/msgexchange/ingress/InboxPollerTest.kt

@@ -1,5 +1,6 @@
 package com.gzzn.omms.msgexchange.ingress
 
+import com.gzzn.omms.msgexchange.domain.ErrorClass
 import com.gzzn.omms.msgexchange.domain.ProcStatus
 import com.gzzn.omms.msgexchange.infra.stub.StubInbox
 import com.gzzn.omms.msgexchange.infra.stub.StubProcState
@@ -40,6 +41,7 @@ class InboxPollerTest {
         poller.pollOnce()
         assertEquals(0, poller.pollOnce())
         pump.tick()
-        assertEquals(ProcStatus.FAILED, stubProc.snapshotOf(id)!!.state)
+        assertEquals(ProcStatus.DEAD, stubProc.snapshotOf(id)!!.state)
+        assertEquals(ErrorClass.MALFORMED, stubProc.snapshotOf(id)!!.errorClass)
     }
 }