test(issue26): classify MAM_ID_POST_DISCOVERED as a string compare (Issue #68)

create_session.sh reads the new adapter fact as "${MAM_ID_POST_DISCOVERED:-0}"
and compares it with "= 1"; test_b5 requires every such default to be
classified.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_issue26_ints.py

@@ -108,6 +108,7 @@ NOT_ARITHMETIC = {
     # sleep's fractional seconds are its meaning here (default 0.5): mam_int would refuse them
     "SKS_QUIESCENT_INTERVAL": "sleep, fractional by default (0.5) - left raw",
     "DELEGATE_JOB_ACK_S": "create_session.sh -> delegate_wait_started, which runs mam_int on it",
+    "MAM_ID_POST_DISCOVERED": "string compare (adapter fact from lib_py.agents facts)",
 }