Unified logging: rsyslog as the system logger, the ForgeFIRM log tree

rsyslog replaces busybox syslogd/klogd (VIRTUAL-RUNTIME_base-utils-syslog,
trimmed PACKAGECONFIG) and becomes the only log writer: the appended
/etc/rsyslog.conf sets the inputs and the ff_line format and includes
the per-logger rules that `forgectrl --render-syslog` renders from the
machine settings at boot. forgefirm-logrotate becomes forgefirm-logging:
render before rsyslog starts (S19), sweep the pre-syslog log files into
/data/forgefirm/legacy-logs once, and rotate the tree at boot and hourly
by rename + HUP instead of copytruncate. Pins bumped to the pushed
forgectrl (syslog emitter, Logs tab, export), grblHAL-glowforge (syslog
emitter) and python3-gfhardware apps (syslog handlers, capture dir);
the CI harnesses set FFLOG_STDERR=1 so failure diagnostics keep the
controller's log lines. BRINGUP carries the bench validation checklist
(Next work item 14); this is an image change and rides the next flash.

scripts/bench/laser_lifecycle_test.py

@@ -129,7 +129,8 @@ class Session:
         with open(conf, "w") as f:
             f.write("laser_disarm_s = %d\n" % disarm_s)
         verdict = os.path.join(self.workdir, "cooling.state")
-        env = dict(os.environ, GF_VERDICT_FILE=verdict, GFHOME_CONF=conf)
+        env = dict(os.environ, GF_VERDICT_FILE=verdict, GFHOME_CONF=conf,
+                   FFLOG_STDERR="1")
         env.pop("GFSINK", None)
         self.stop = threading.Event()
         self.pub = threading.Thread(target=publish_verdicts,