test(827): capture Gate0 runtime evidence

docs/compaction-refresh/evidence/raw/P4-so-peercred.txt

@@ -0,0 +1,23 @@
+$ python3 docs/compaction-refresh/probes/p4_peercred_probe.py
+machine_assertions=PASS
+server_pid=4013762 server_uid=1001 server_gid=1001
+socket_path=/tmp/gate0-p4-nl1_8ap2/broker.sock
+directory_mode=0700 socket_mode=0600
+SO_PEERCRED pid=4013768 uid=1001 gid=1001
+client_claim={"exe": "/usr/bin/python3.11", "pid": 4013768, "ppid": 4013762, "starttime_ticks": 365927069, "uid": 1001}
+proc_observed={"exe": "/usr/bin/python3.11", "pid": 4013768, "ppid": 4013762, "starttime_ticks": 365927069, "uid": 1001}
+pid_match=True
+uid_match=True
+starttime_match=True
+client_exit_status=0
+same_principal_socket=true
+posture=0700 parent + 0600 socket excludes other UIDs, but does not prevent the same UID from unlinking/rebinding; distinct-principal system service remains required for a claim stronger than T-C against same-UID counterfeit replacement
+
+$ id
+uid=1001(hermes) gid=1001(hermes) groups=1001(hermes),40(src),100(users),996(docker)
+
+$ uname -srmo
+Linux 6.1.0-48-amd64 x86_64 GNU/Linux
+
+$ getconf CLK_TCK
+100